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Coordination Compounds — Chemistry STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceChemistryCoordination Compounds4 Marks
Question
Read the passage given below and answer the following questions:

For understanding the structure and bonding in transition metal complexes, the magnetic properties are very helpful. Low spin complexes are generally diamagnetic because of pairing of electrons, whereas high spin complexes are usually paramagnetic because of presence of unpaired electrons. Larger the number of unpaired electrons, stronger will be the paramagnetism. However magnetic behaviour of a complex can be confirmed from magnetic moment measurement. Magnetic moment $\mu=\sqrt{\text{n(n+2)}}\text{B.M.}$ where n = number of unpaired electrons. Greater the number of unpaired electrons, more will be the magnetic moment.

In these questions (Q. No. i-iv), a statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
The following questions are multiple choice questions. Choose the most appropriate answer:

  1. Assertion: Both [Cr(H2O)6]2+ and [Fe(H2O)6]2+ have same magnetic moment.

Reason: Number of unpaired electrons in Cr2+ and Fe2+ are same.

  1. Assertion: [Fe(H2O)5NO]SO4 is paramagnetic.

Reason: The Fe in [Fe(H2O)5NO]SO4 has three unpaired electrons.

  1. Assertion: [Co(en)3]3+ is paramagnetic.

Reason: It is an inner orbital complex.

  1. Assertion: [Ni(CO)4] is diamagnetic and tetrahedral in shape.

Reason: [Ni(CO)4] contains no unpaired electrons and involves dsp2 hybridisation.

  1. Assertion: [Ni(CN)4]2- is diamagnetic complex.

Reason: It involves dsp2 hybridisation and there is no unpaired electron.

✓

Answer

  1. (a) Assertion and reason both are correct statements and reason is correct explanation for assertion.

Explanation:

Spinonlymagneticmoment, $\mu=\sqrt{\text{n(n+2)}}$ where n = number of unpaired electrons. 

As the number of unpaired electrons in Cr2+[(Ar)3d4] and Fe2+[(Ar)3d6] are same, hence [Cr(H2O)6]2+ and [Fe(H2O)6]2+ will have same magnetic moment.

  1. (a) Assertion and reason both are correct statements and reason is correct explanation for assertion.

Explanation:

Fe+: [Ar)3d74s0

When the weak field ligand H2O and strong field ligand NO+ attack, the configuration changes as follows: Fe+: [Ar)3d74s0

$\therefore$ Fe2+ has 3 unpaired electrons.

  1. (d) Assertion is wrong statement but reason is correct statement.

Explanation:

In presence of strong ethylenediamine ligand the electrons get paired.

Thus inner orbital complex with no unpaired electrons.

  1. (c) Assertion is correct statement but reason is wrong statement.

Explanation:

[Ni(CO)4] contains Ni(O).

CO is strong ligand thus,

  1. (a) Assertion and reason both are correct statements and reason is correct explanation for assertion.

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Similar questions

Read the passage given below and answer the following questions:

Aldehydes and ketones are reduced to primary and secondary alcohols respectively by NaBH4 or LiAlH4 as well as catalytic hydrogenation. The carbonyl group of aldehydes and ketones is reduced to  group on treatment with Zn-Hg and cone. HCl (Clemmensen reduction) or with hydrazine followed by NaOH or KOH in highly boiling solvent such as ethylene glycol (Wolff-Kishner reduction).Aldehydes differ from ketones in their oxidation reactions. Aldehydes are easily oxidised to carboxylic acids on treatment with HNO3, KMnO4, K2Cr2O7 etc. Even mild oxidising agents mainlyTollens' reagent and Fehling's solution also oxidise aldehydes. Ketones are generally oxidised under vigorous conditions i.e., strong oxidising agents and at elevated temperatures, to give mixture of carboxylic acids having lesser number of C-atoms than the parent ketone.

The following questions are multiple choice questions. Choose the most appropriate answer:

  1. Which of the following cannot be made by reduction of ketone or aldehyde with NaBH4 in methanol?
  1. 1-Butanol
  2. 2-Butanol
  3. 2-Methyl-1-propanol
  4. 2-Methyl-2-propanol
  1. The carbonyl compound producing an optically active product by reaction with LiAlH4 is:
  1. Propanone
  2. Butanone
  3. 3-pentanone
  4. Benzophenone
  1. A substance C4H10O (X) yields on oxidation a compound C4H8O which gives an oxime and a positive iodoform test. The substance X on treatment with cone. H2SO4 gives C4H8. The structure of the compound (X) is:
  1. CH3CH2CH2CH2OH
  2. CH3CH(OH)CH2CH3
  3. (CH3)3COH
  4. CH3CH2 - O - CH2CH3
  1. In the oxidation of  by acidified K2Cr2O7, the products are:

  1. $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3-\ ^\text{14}\text{C}-\text{OH}$ and $\text{CH}_3\text{CH}_2\text{COOH}$

  2. $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ||\\\text{CH}_3(\text{CH}_2)_2\text{COOH}-\text{C}-\text{OH}$ and $ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{COOH}$

  3. $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 14\\\text{CH}_3\text{CH}_2\text{CH}_2\text{COOH}+\text{HCOOH}$

  4. None of these.

  1. The appropriate reagent for the following transformation is:

  1. $\text{Na}_2\text{NH}_2,^-\text{OH}$

  2. $\text{NaBH}_4$

  3. $\frac{\text{H}_2}{\text{Ni}}$

  4. $\text{AICl}_3$

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Read the passage given below and answer the following questions:
Nucleophilic substitution reactions are of two types; substitution nucleophilic bimolecular (SN2) and substitution nucleophilic unimolecular (SN1) depending on molecules taking part in determining the rate of reaction. Reactivity of alkyl halide towards SN1 and SN2 reactions depends on various factors such as steric hindrance, stability of intermediate or transition state, and polarity of solvent. SN2 reaction mechanism is favoured mostly by primary alkyl halide then secondary and then tertiary. This order is reversed in case of SN1 reactions.
The following questions are multiple choice questions. Choose the most appropriate answer:
  1. Which of the following is most reactive towards nucleophilic substitution reaction?
  1. C6H5Cl
  2. CH2 = CHCl
  3. ClCH2CH = CH2
  4. CH3CH = CHCl
  1. Isopropyl chloride undergoes hydrolysis by:
  1. SN1 mechanism.
  2. SN2 mechanism.
  3. SN1 and SN2 mechanism.
  4. Neither SN1 nor SN2 mechanism.
  1. The most reactive nucleophile among the following is:
  1. CH3O-
  2. C6H5O-
  3. (CH3)2CHO-
  4. (CH3)3CO-
  1. Tertiary alkyl halides are practically inert to substitution by SN2 mechanism because of:
  1. Insolubility.
  2. Instability.
  3. Inductive effect.
  4. Stearic hindrance.
  1. Which of the following is the correct order of decreasing SN2 reactivity?
  1. RCH2X > R2CHX > R3CX
  2. R3CX > R2CHX > RCH2X
  3. R2CHX > R3CX > RCH2X
  4. RCH2X > R3CX > R2CHX
→
Molar conductivity of ions are given as product of charge on ions to their ionic mobilities and Faradays constant.
$\lambda_\text{A}\text{n}+=\text{n}\mu_\text{A}\text{n}+\text{F}$ (here $\mu$ is the ionic mobility of An+)
For electrolytes say AxBy, molar conductivity is given by
$\lambda_{\text{m}(\text{A}_\text{x}\text{B}_\text{y})}=\text{x}_\text{n}\mu_{\text{A}^\text{n}}+\text{F}+\text{y}_\text{m}\lambda_{\text{A}^\text{m}}-\text{F}$
Ions
Ionic mobility
K+
7.616 × 10-4
Ca2+
12.33 × 10-4
Br-
8.09 × 10-4
$\text{SO}_{4}^{2-}$
16.58 × 10-4
The following questions are multiple choice questions. Choose the most appropriate answer:
  1. At infinite dilution, the equivalent conductance of CaSO4 is:
  1. 256 × 10-4
  2. 279
  3. 23.7
  4. 2.0 × 10-8
  1. If the degree of dissociation of CaSO4 solution is 10% then equivalent conductance of CaSO4 is:
  1. 3.59
  2. 36.9
  3. 27.9
  4. 30.6
  1. The correct order of equivalent conductance at infinite dilution of LiCl, NaCl, KCl is:
  1. LiCl = NaCl = KCl
  2. LiCl > NaCl > KCl
  3. KCl > LiCl > NaCl
  4. KCl > NaCl > LiCl
  1. What is the unit of equivalent conductivity?
  1. ohm-1 cm2 eq-1
  2. ohm cm2 eq-1
  3. ohm-1 cm eq-1
  4. ohm cm-2eq-2
  1. If the molar conductance value of Ca2+ and Cl- at infinite dilution are 118.88 × 10-4m2 mho mol-1 and 77.33 × 10-4m2 mho mol-1 respectively then the molar conductance of CaCl2 (in m2 mho mol-1) will be:
  1. 120.18 × 10-4
  2. 135 × 10-4
  3. 273.54 × 10-4
  4. 192.1 × 10-4
→
The progress of the reaction, $\text{A}\rightleftharpoons\text{nB}$ with time is represented in the following figure:

The following questions are multiple choice questions. Choose the most appropriate answer:
  1. What is the value of n?
  1. 1
  2. 2
  3. 3
  4. 4
  1. Find the value of the equilibrium constant.
  1. 0.6M
  2. 1.2M
  3. 0.3M
  4. 2.4M
  1. The initial rate of conversion of A will be:
  1. 0.1 mol L-1hr-1
  2. 0.2 mol L-1hr-1
  3. 0.4 mol L-1hr-1
  4. 0.8 mol L-1hr-1
  1. For the reaction, if $\frac{\text{d}[\text{B}]}{\text{dt}}=2\times10^{-4},$ value of $-\frac{\text{d}[\text{A}]}{\text{dt}}$ will be:
  1. 2 × 10-4
  2. 10-4
  3. 4 × 10-4
  4. 0.5 × 10-4
  1. Which factor has no effect on rate of reaction?
  1. Temperature.
  2. Nature of reactant.
  3. Concentration of reactant.
  4. Molecularity.
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Read the passage given below and answer the following questions:

Aldehydes and ketones having acetyl group $\left(\begin{array}{c}\ \ \ \ \ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ ||\\\ \ \ \text{CH}_3-\text{C}-\end{array}\right)$ are oxidised by sodium hypohalate (NaOX) or halogen and alkali (X2 + OH-) to corresponding sodium salt having one carbon atoms less than the carbonyl compound and give a haloform.

$\ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ ||\\\text{R}-\text{C}-\text{CH}_3\xrightarrow[\text{orX}_2+\text{NaOH}]{\text{NaOX}}\\ \ \ \ \ \ \ \ \ \text{O}\\\ \ \ \ \ \ \ \ ||\\\text{R}-\text{C}-\stackrel{-}{\hbox{ O}}\stackrel{+}{\hbox{Na}}+\text{CHX}_3(\text{X = Cl, Br, I})$

Sodium hypoiodite (NaOl) when treated with compounds containing CH3CO-group gives yellow precipitate of iodoform. Haloform reaction does not affect a carbon-carbon double bond present in the compound.

The following questions are multiple choice questions. Choose the most appropriate answer:

  1. Which of the following compounds will give positive iodoform test?
  1. Isopropyl alcohol.
  2. Propionaldehyde.
  3. Ethylphenyl ketone.
  4. Benzyl alcohol.
  1. Which of the following compounds is not formed in iodoform reaction of acetone?
  1. CH3COCH2l
  2. lCH2COCH2l
  3. CH3COCHl2
  4. CH3COCl3
  1. For the given set of reactions,

starting compound A corresponds to:

  1. In the following reaction sequence, the correct structures of E, F and G are:

(* implies 13C labelled carbon)

  1. An organic compound 'A' has the molecular formula C3H6O. It undergoes iodoform test. When saturated with HCl it gives 'B' of molecular formula C9H14O. 'A' and 'B' respectively are:
  1. propanal and mesityl oxide.
  2. Propanone and mesityl oxide.
  3. propanone and 2,6-dimethyl-2,5-hepta-dien-4-one.
  4. propanone and propionaldehyde.
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Read the passage given below and answer the following questions:

Amines are produced when an alcoholic solution of ammonia and an alkyl or a benzyl halide is heated in a sealed tube at 373K. This reaction is called ammonolysis and usually gives a mixture of primary, secondary and tertiary amines along with some quarternary ammonium salts. This reaction is an example of nucleophilic substitution reaction in which ammonia acts as a nucleophile due to the presence of a lone pair of electrons on the nitrogen atom. However this method cannot be used for the preparation of aryl amines. One of the most convenient methods for the preparation of aryl amines is reduction of nitro compounds. Aryl amines can also be prepared by reduction of nitrites or Gabriel phthalimide synthesis.

A statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: Ammonolysis of alkyl halides only produces 2° amines.

Reason: Ammonolysis of alkyl halides involves the reaction between alkyl halides and alcoholic ammonia.

  1. Assertion: Gabriel-phthalimide reaction can be used to prepare both aryl and alkyl primary amines.

Reason: Aryl halides are more reactive alkyl halides towards nucleophilic substitution reactions.

  1. Assertion: Anunonolysis method cannot be used for the preparation of aryl amines.

Reason: Aryl halides are much less reactive than alkyl halides towards nucleophilic substitution reaction.

  1. Assertion: Ammonolysis can be used to prepare pure primary amines.

Reason: Ammonolysis of haloalkanes lead to multiple ammonium salts.

  1. Assertion: Aromatic 1º amines can not be prepared by Gabriel phthalimide synthesis.

Reason: Aryl halides do not undergo nucleophilic substitution with anion formed by phthalimide.

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Read the passage given below and answer the following questions:

The sequence of bases along the DNA and RNA chain establishes its primary structure which controls the specific properties of the nucleic acid. An RNA molecule is usually a single chain ofribose-containing nucleotide. On the basis of X-ray analysis of DNA, J.D., Watson and EH.C. crick (shared noble prize in 1962) proposed a three dimensional secondary structure for DNA. DNA molecule is a long and highly complex, spirally twisted, double helix, ladder like structure. The two polynucleotide chains or strands are linked up by hydrogen bonding between the nitrogeneous base molecules of their nucleotide monomers. Adenine (purine) always links with thymine (pyrimidine) with the help of two hydrogen bonds and guanine (purine) with cytosine (pyrimidine) with the help of three hydrogen bonds. Hence, the two strands extend in opposite directions, i.e., are antiparallel and complimentary.

  1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
  2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
  3. Assertion is correct statement but reason is wrong statement.
  4. Assertion is wrong statement but reason is correct statement.
  1. Assertion: DNA molecules and RNA molecules are found in the nucleus of a cell.

Reason: There are two types of nitrogenous bases, purines and pyrimidines. Adenine (A) and guanine (G) are substituted purines; cytosine (C), thymine (T) and uracil (U) are substituted pyrimidines.

  1. Assertion: In both DNA and RNA, heterocyclic base and phosphate ester linkages are at C-1' and C-5' respectively of the sugar molecule.

Reason: Nucleotides and nucleosides mainly differ from each other in presence of phosphate units.

  1. Assertion: The backbone of RNA molecule is a linear chain consisting of an alternating units of a heterocylic base, D-ribose and a phosphate.

Reason: The segment of DNA which acts as the instruction manual for the synthesis of protein is ribose.

  1. Assertion: The double helical structure of DNA was proposed by Emil Fischer.

Reason: A nucleoside is an N-glycoside of heterocyclic base.

  1. Assertion: In DNA, the complementary bases are, adenine and guanine; thymine and cytosine.

Reason: The phenomenon of mutation is chemical change in DNA molecule.

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Read the passage given below and answer the following questions:
Amines are alkyl or aryl derivatives of ammonia formed by replacement of one or more hydrogen atoms. Alkyl derivatives are called aliphatic amines and aryl derivatives are known as aromatic amines. The presence of aromatic amines can be identified by performing dye test. Aniline is the simplest example of aromatic amine. It undergoeselectrophilic substitution reactions in which -NH2 group strongly activates the aromatic ring through delocalisation of lone pair of electrons of N-atom. Aniline undergoes electrophilic substitution reactions. Ortho and para positions to the -NH2 group become centres of high electrons density. Thus, -NH2 group is ortho and para-directing and powerful activating group.
The following questions are multiple choice questions. Choose the most appropriate answer:
  1. Cyclohexylamine and aniline can be distinguished by:
  1. Hinsberg test.
  2. carbylamine test.
  3. Lassaigne test.
  4. azo dye test.
  1. Which of the following compounds gives dye test?
  1. Aniline.
  2. Methyl amine.
  3. Diphenyl amine.
  4. Ethyl amine.
  1. Aniline when acetylated, the major product on nitration followed by alkaline hydrolysis gives:
  1.  Acetanilide.
  2. o-nitroacetanitide.
  3. p-nitroaniline.
  4. m-nitroanitine.
  1. Oxidation of aniline with manganese dioxide and sulphuric acid produces:
  1. Phenylhydroxylamine.
  2. Nitrobenzene.
  3. p-benzoquinone.
  4. Phenol.
  1. Aniline when treated with cone. HNO3 and H2S04 gives:
  1.  p-phenylenediamine.
  2. m-nitroaniline.
  3. p-benzoquinone.
  4. Nitrobenzene.
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Read the passage given below and answer the following questions:

The molecular compounds which are formed from the combination of two or more simple stable compounds and retain their identity in the solid as well as in the dissolved state are called coordination compounds. Their properties are completely different from the constituents. ln coordination compounds, the central metal atom or ion is linked to a number ofions or neutral molecules, called ligands, by coordinate bonds. For example, Dimethylglyoxime (dmg) is a bid en date ligand chelating large amounts of metals. When dimethyl glyoxime is added to alcoholic solution of NiCl2 and ammonium hydroxide is slowly added to it, a rosy red precipitate of a complex is formed.

The following questions are multiple choice questions. Choose the most appropriate answer:

  1. The structure of the complex is:

  1. Oxidation number of Ni in the given complex is:
  1. +3
  2. +1
  3. +2
  4. Zero
  1. Hybridisation and structure of the complex is:
  1. Sp3, tetrahedral.
  2. dsp2, square planar.
  3. Sp3, square planar.
  4. Sp3d, trigonal bipyramidal.
  1. Which of the following is true about this complex?
  1. It is paramagnetic, containing 2 unpaired electrons.
  2. It is paramagnetic, containing 1 unpaired electron.
  3. It is paramagnetic, containing 4 unpaired electrons.
  4. It is diamagnetic with no unpaired electron.
  1. Which one will give test for Fe3+ ions in the solution?
  1. [Fe(CN)6]3-
  2. [Fe(CN)6]2-
  3. (NH4)2SO4·FeSO4·6H2O
  4. Fe2(S04)3
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What is the most suitable pKa value of the substituted propylamine formed with substituent "X" with electronegativity 3.0
(i)10.67 (ii)10.08 (iii) 10.15 (iv)11.10
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