Embibe Experts Solutions for Chapter: Some Basic Concepts of Chemistry, Exercise 3: Exercise-3

The density of a solution prepared by dissolving $120 \mathrm{g}$ of urea $(\mathrm{mol}.$ mass $=60 \mathrm{u})$ in $1000 \mathrm{g}$ of water is $1.15 \mathrm{g}/\mathrm{mL}$. What is the molarity of this solution?

At $300 \mathrm{K}$ and $1 \mathrm{atm}, 15 \mathrm{mL}$ of a gaseous hydrocarbon requires $375 \mathrm{mL}$ air containing $20\%{\mathrm{O}}_2$ by volume for complete combustion. After combustion the gases occupy $330 \mathrm{mL}$. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is :

$1 \mathrm{gram}$ of a carbonate $\left({\mathrm{M}}_2{\mathrm{CO}}_3\right)$ on treatment with excess $\mathrm{HCl}$ produces $0.01186$ mole of ${\mathrm{CO}}_2$. The molar mass of ${\mathrm{M}}_2{\mathrm{CO}}_3$ in $\mathrm{g} {\mathrm{mol}}^{-1}$ is:

The most abundant elements by mass in the body of a healthy human adult are: Oxygen ($61.4\%$), Carbon ($22.9\%$), Hydrogen ($10.0\%$) and Nitrogen ($2.6\%$). The weight which a $75 \mathrm{kg}$ person would gain if all ${}^1\mathrm{H}$ atoms are replaced by ${}^2\mathrm{H}$ atoms is:

Three moles of ${\mathrm{B}}_2{\mathrm{H}}_6$ are completely reacted with methanol. The number of moles of boron containing product formed is

Silver (atomic weight = $108 \mathrm{g} {\mathrm{mol}}^{-1}$ ) has a density of $10.5 \mathrm{g} {\mathrm{cm}}^{-3}$. The number of silver atoms on a surface of area ${10}^{-12} {\mathrm{m}}^2$ can be expressed in scientific notation as $\mathrm{y}\times {10}^{\mathrm{x}}$. The value of x is

For the reaction : ${\mathrm{I}}^{-}+{\mathrm{CIO}}_3^{-}+{\mathrm{H}}_2{\mathrm{SO}}_4⟶{\mathrm{Cl}}^{-}+{\mathrm{HSO}}_4^{-}+{\mathrm{I}}_2$ The correct statement(s) in the balanced equation is/are :

The ammonia prepared by treating ammonium sulphate with calcium hydroxide is completely used by ${\mathrm{NiCl}}_2·6{\mathrm{H}}_2\mathrm{O}$ to form a stable coordination compound. Assume that both the reactions are $100\%$ complete. If $1584 \mathrm{g}$ of ammonium sulphate and $952 \mathrm{g}$ of ${\mathrm{NiCl}}_2·6{\mathrm{H}}_2\mathrm{O}$ are used in the preparation, the combined weight (in grams) of gypsum and the nickel-ammonia coordination compound thus produced is _____

(Atomic weights in $\mathrm{g} {\mathrm{mol}}^{-1}:\mathrm{H}=1, \mathrm{N}=14, \mathrm{O}=16, \mathrm{S}=32, \mathrm{Cl}=35.5, \mathrm{Ca}=40, \mathrm{Ni}=59$)