MCQ
What changes does not occur when $K_2Cr_2O_7$ react with $H_2O_2$ solution
- AOrange colour of solution turns blue
- ✓$O.S$. of $Cr$ atom decreases
- C$O.S.$ of $Cr$ atom remains constant
- DNone of these
✓
Answer
Correct option: B.
$O.S$. of $Cr$ atom decreases
b
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Which is the correct increasing order of electronegativity of halides?
Product $(P)$ is
→Which is the strongest acid ? ($pKa$ value is given in the bracket)
→Products of the following reaction $C{{H}_{3}}C\equiv C\,C{{H}_{2}}C{{H}_{3}}\underset{(2)\,Hydrolysis}{\mathop{\xrightarrow{(1)\,{{O}_{3}}}}}\,\,\,\,...\text{are}$
→Identify the metal that forms colourless compounds.
By how much will the potential of half cell $Cu^{2+} / Cu$ change if the solution is diluted to $100$ times at $298\ K$
→The formula of sodium nitroprusside is
$\mathrm{CO}_{2}$ gas is bubbled through water during a soft drink manufacturing process at $298\, \mathrm{~K}$. If $\mathrm{CO}_{2}$ exerts a partial pressure of $0.835$ bar then $x \,\mathrm{~m} \,\mathrm{~mol}$ of $\mathrm{CO}_{2}$ would dissolve in $0.9\,\mathrm{~L}$ of water. The value of $x$ is $.....$ (Nearest integer)
→(Henry's law constant for $\mathrm{CO}_{2}$ at $298\, \mathrm{~K}$ is $1.67 \times 10^{3}$ $bar$)
Which of the following reacts with $NaN{O_2} + HCl$ to give phenol
→Tollen's reagent is used for the detection of aldehyde when a solution of $\mathrm{AgNO}_3$ is added to glucose with $\mathrm{NH}_4 \mathrm{OH}$ then gluconic acid is formed
→$ \mathrm{Ag}^{+}+\mathrm{e}^{-} \rightarrow \mathrm{Ag} ; \mathrm{E}_{\text {red }}^{\circ}=0.8 \mathrm{~V} $
$ \mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+\mathrm{H}_2 \mathrm{O} \rightarrow \text { Gluconic acid }\left(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_7\right)+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} ; \mathrm{E}_{\text {oxd }}^{\circ}=-0.05 \mathrm{~V} $
$ \mathrm{Ag}\left(\mathrm{NH}_3\right)_2^{+}+\mathrm{e}^{-} \rightarrow \mathrm{Ag}(\mathrm{s})+2 \mathrm{NH}_3 ; \mathrm{E}_{\text {red }}^{\circ}=0.337 \mathrm{~V}$
[Use $2.303 \times \frac{\mathrm{RT}}{\mathrm{F}}=0.0592$ and $\frac{\mathrm{F}}{\mathrm{RT}}=38.92$ at $298 \mathrm{~K}$ ]
$1.$ $2 \mathrm{Ag}^{+}+\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+\mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{Ag}(\mathrm{s})+\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_7+2 \mathrm{H}^{+}$
Find $\ln \mathrm{K}$ of this reaction.
$(A)$ $66.13$ $(B)$ $58.38$ $(C)$ $28.30$ $(D)$ $46.29$
$2.$ When ammonia is added to the solution, $\mathrm{pH}$ is raised to $11$ . Which half-cell reaction is affected by $\mathrm{pH}$ and by how much?
(A) $E_{\text {oxd }}$ will increase by a factor of $0.65$ from $E_{\text {oxd }}^{\circ}$
(B) $E_{\text {oxd }}$ will decrease by a factor of $0.65$ from $E_{\mathrm{cod}}^{\prime}$
(C) $\mathrm{E}_{\text {red }}$ will increase by a factor of $0.65$ from $\mathrm{E}_{\text {rod }}^{\circ}$
(D) $E_{\text {red }}$ will decrease by a factor of $0.65$ from $E_{\text {rod }}^2$
$3.$ Ammonia is always is added in this reaction. Which of the following must be incorrect?
$(A)$ $\mathrm{NH}_3$ combines with $\mathrm{Ag}^{+}$to form a complex.
$(B)$ $\mathrm{Ag}\left(\mathrm{NH}_3\right)_2^{+}$is a stronger oxidising reagent than $\mathrm{Ag}^{+}$.
$(C)$ In absence of $\mathrm{NH}_3$ silver salt of gluconic acid is formed.
$(D)$ $\mathrm{NH}_3$ has affected the standard reduction potential of glucose/gluconic acid electrode.
Give the answer question $1,2$ and $3.$