Embibe Experts Solutions for Chapter: Some Basic Concepts of Chemistry, Exercise 1: JEE Main - 1 February 2023 Shift 2

When a hydrocarbon $\mathrm{A}$ undergoes combustion in the presence of air, it requires $9.5$ equivalents of oxygen and produces $3$ equivalents of water. What is the molecular formula of $\mathrm{A}$?

The volume of $\mathrm{HCl}$, containing $73\mathrm{g} {\mathrm{L}}^{-1}$, required to completely neutralise $\mathrm{NaOH}$ obtained by reacting $0.69 \mathrm{g}$ of metallic sodium with water, is _____ $\mathrm{mL}$. (Nearest Integer)

(Given : molar Masses of $\mathrm{Na},\mathrm{Cl},\mathrm{O},\mathrm{H}$ are $23,35.5,16$ and $1\mathrm{g} {\mathrm{mol}}^{-1}$ respectively)

Some amount of dichloromethane $\left({\mathrm{CH}}_2{\mathrm{Cl}}_2\right)$ is added to $671.141\mathrm{mL}$ of chloroform $\left({\mathrm{CHCl}}_3\right)$ to prepare $2.6\times {10}^{-3}\mathrm{M}$ solution of ${\mathrm{CH}}_2{\mathrm{Cl}}_2\left(\mathrm{DCM}\right)$. The concentration of $\mathrm{DCM}$ is _____ ppm (by mass).

Given: Atomic mass : $\mathrm{C}=12;\mathrm{H}:1;\mathrm{Cl}=35.5$ density of ${\mathrm{CHCl}}_3=1.49\mathrm{g} {\mathrm{cm}}^{-3}$

On complete combustion, $0.492 \mathrm{g}$ of an organic compound gave $0.792 \mathrm{g}$ of ${\mathrm{CO}}_2$. The $\%$ of carbon in the organic compound is (Nearest integer)

Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of $11.5 \mathrm{g}$ of zinc with excess $\mathrm{HCl}$ is $\mathrm{L}$ (Nearest integer)
(Given : Molar mass of $\mathrm{Zn}$ is $65.4 \mathrm{g} {\mathrm{mol}}^{-1}$ and Molar volume of ${\mathrm{H}}_2$ at $\mathrm{STP}=22.7 \mathrm{L}$ )

Assume carbon burns according to following equation :
$2\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2( \mathrm{g})\to 2\mathrm{CO}\text{ (s) }$
when $12 \mathrm{g}$ carbon is burnt in $48 \mathrm{g}$ of oxygen, the volume of carbon monoxide produced is $\_\_\_\_\_\_\times {10}^{-1} \mathrm{L}$ at STP [nearest integer]

[Given : Assume $\mathrm{CO}$ as ideal gas, Mass of $\mathrm{C}$ is $12 \mathrm{g} {\mathrm{mol}}^{-1}$, mass of $O$ is $16 \mathrm{g} {\mathrm{mol}}^{-1}$ and molar volume of an idal gas at STP is $22.7 \mathrm{L} {\mathrm{mol}}^{-1}$ ]

The density of $3\mathrm{M}$ solution of $\mathrm{NaCl}$ is $1.0 \mathrm{g} {\mathrm{mL}}^{-1}$. Molality of the solution is $\_\_\_\_\_\_\times {10}^{-2} \mathrm{m}$ (Nearest integer).

Given: Molar mass of $\mathrm{Na}$ and $\mathrm{Cl}$ is $23$ and $35.5 \mathrm{g}$ ${\mathrm{mol}}^{-1}$ respectively.

The molality of a $10\%(\mathrm{v}/\mathrm{V})$ solution of di-bromine solution in ${\mathrm{CCl}}_4$ (carbon tetrachloride) is $\mathrm{x}$ '. $\mathrm{x}=$ $\_\_\_\_\_\times {10}^{-2}\mathrm{M}$. (Nearest integer)

[Given : molar mass of ${\mathrm{Br}}_2=160 \mathrm{g} {\mathrm{mol}}^{-1}$

atomic mass of $\mathrm{C}=12 \mathrm{g} {\mathrm{mol}}^{-1}$

atomic mass of $\mathrm{Cl}=35.5 \mathrm{g} {\mathrm{mol}}^{-1}$

density of dibromine $=3.2 \mathrm{g} {\mathrm{cm}}^{-3}$

density of $\left.{\mathrm{CCl}}_4=1.6 \mathrm{g} {\mathrm{cm}}^{-3}\right]$