Question
How the phosphorus is analysed in organic compound? Explain.
✓
Answer
For the estimation of phosphorus. When the quantity of organic compound is heated with fumed nitric acid, the phosphorus present in it gets oxidized into phosphoric acid $\left( H _3 PO _4\right)$. On adding ammonia and ammonium molybdate solution, a precipitate of ammonium phosphomolybdate $\left[\left( NH _4\right)_3 PO _4 \cdot 12 MoO _3\right]$ is obtained or by adding magnesia mixture to phosphoric acid it is precipitated in form of $MgNH _4 PO _4$, on the combustion of which $Mg _2 P _2 O _7$ is obtained.
Let the mass of organic compound $= m _1 g$ and the mass of ammonium phosphomolybdate is $m _1 g$. Molar mass of $\left( NH _4\right)_3 PO _4 \cdot 12 MoO _3=1877 gm$
Hence $\%$ of phosphorus $=\frac{31 \times m _1 \times 100}{1877 \times m } \%$
When phosphorus is analysed in form of $Mg _2 P _2 O _7$,
then $\%$ of phosphorus $=\frac{62 \times m_1 \times 100}{222 \times m}$
Here mass of $Mg _2 P _2 O _7=222 u$
Mass of organic compound $= m _1 g$
Mass of formed $Mg _2 P _2 O _7= m$, and mass of two phosphorus atoms in $Mg _2 P _2 O _7$ is 62 .
Let the mass of organic compound $= m _1 g$ and the mass of ammonium phosphomolybdate is $m _1 g$. Molar mass of $\left( NH _4\right)_3 PO _4 \cdot 12 MoO _3=1877 gm$
Hence $\%$ of phosphorus $=\frac{31 \times m _1 \times 100}{1877 \times m } \%$
When phosphorus is analysed in form of $Mg _2 P _2 O _7$,
then $\%$ of phosphorus $=\frac{62 \times m_1 \times 100}{222 \times m}$
Here mass of $Mg _2 P _2 O _7=222 u$
Mass of organic compound $= m _1 g$
Mass of formed $Mg _2 P _2 O _7= m$, and mass of two phosphorus atoms in $Mg _2 P _2 O _7$ is 62 .
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
More "2 Marks Questions" from PART - 2 CH - 8 Organic Chemistry: Some Basic Principles and Techniques→PART - 2 CH - 8 Organic Chemistry: Some Basic Principles and Techniques — all question types→Chemistry STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→
Similar questions
Empirical formula of a compound X (molar mass 78g mol-1) is CH. Write its molecular formula.
Use Lewis symbols to show electron transfer between the following atoms to form cations and anions :
(a) K and S (b) Ca and O (c) Al and N .
(a) K and S (b) Ca and O (c) Al and N .
The enthalpy of vapourisation of CCl4 is 30.5kJ mol–1. Calculate the heat required for the vapourisation of 284g of CCl4 at constant pressure. (Molar mass of CCl4 = 154g mol–1).
Arrange the following in order of decreasing bond angles.
→- $\text{CH}_4, \text{NH}_3, \text{H}_2\text{O}, \text{BF}_3, \text{C}_2\text{H}_2$
- $\text{NH}_3, \text{NH}^‑_2, \text{NH}^+_4$
Magnesium and Lithium both form nitride, why? Write the equation for formation of their nitride.
Which is more polar: CO2 or N2O? Give reason.
In following compound calculate the hybridisation in each carbon.
(i) $CH _3 Cl$
(ii) $H C O N H _2$
(iii) $CH _3 CN$
→(i) $CH _3 Cl$
(ii) $H C O N H _2$
(iii) $CH _3 CN$
A sample of 1.0mol of a monoatomic ideal gas is taken through a cyclic process of expansion and compression as shown in Fig. What will be the value of $\Delta\text{H}$ for the cycle as a whole?
→
Compound with carbon-carbon double bond, such as ethylene (C2H4) and hydrogen in a reaction is called hydrogenation.
→$\text{C}_2\text{H}_4(\text{g})+\text{H}_2(\text{g})\overrightarrow{\ \ \ \ \ \ }\ \text{C}_2\text{H}_6(\text{g})$
Calculate enthalpy change for the reaction using the following combustion data:$\text{C}_2\text{H}_4(\text{g})+3\text{O}_2(\text{g})\overrightarrow{\ \ \ \ \ }\ 2\text{CO}_2(\text{g})+2\text{H}_2\text{O(g)};$ $\Delta\text{H}=-1401\text{kJ/ mol}$
$\text{C}_2\text{H}_6(\text{g})+\frac{7}{2}\text{O}_2(\text{g})\overrightarrow{\ \ \ \ \ \ }\ 2\text{CO}_2(\text{g})+3\text{H}_2\text{O(l)};$ $\Delta\text{H}=-1550\text{kJ/ mol}$
$\text{H}_2(\text{g})+\frac{1}{2}\text{O}_2(\text{g})\overrightarrow{\ \ \ \ \ \ }\ \text{H}_2\text{O(l)};$ $\Delta\text{H}=-286.0\text{kJ/ mol}$
In astronomical observation, signals observed from the distant stars are generally weak. If the photon detector receives a total of $3.15 \times 10^{-18}$ $J$ from the radiations of 600 nm , calculate the number of photons received by the detector.
→