S C Kheterpal, S N Dhawan and, P N Kapil Solutions for Chapter: Some Basic Concepts of Chemistry, Exercise 22: Competition Focus

Copper reacts with nitric acid to form copper ($\mathrm{II}$) nitrate, nitric oxide and water. The number of nitric acid molecules in the balanced equation 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

Among the following, the number of elements showing only one non-zero oxidation state is

$\mathrm{O}, \mathrm{Cl}, \mathrm{F}, \mathrm{N}, \mathrm{P}, \mathrm{Sn}, \mathrm{Tl}, \mathrm{Na}, \mathrm{Ti}$.

The value of $\mathrm{n}$ in the molecular formula ${\mathrm{Be}}_{\mathrm{n}}{\mathrm{Al}}_2{\mathrm{Si}}_6{\mathrm{O}}_{18}$.

A student performs a titration with different burettes and finds titre values of $25.2 \mathrm{mL}, 25.25 \mathrm{mL}$, and $25.0 \mathrm{mL}$. The number of significant figures in the average titre value is

Reaction of ${\mathrm{Br}}_2$ with ${\mathrm{Na}}_2{\mathrm{CO}}_3$ in aqueous solution gives sodium bromide and sodium bromate with evolution of ${\mathrm{CO}}_2$ gas. The number of sodium bromide molecules involved in the balanced chemical equation is

If the value of Avogadro's number is $6.023 \mathrm{x} {10}^{23} {\mathrm{mol}}^{-1}$ and the value of Boltzmann constant is $1.380 \mathrm{x} {10}^{-23} {\mathrm{JK}}^{-1}$, then the number of significant figures in the calculated value of the universal gas constant 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