Calculate the value of dissociation constant of weak monoacidic base if it dissociates to $2 \%$ in 0.1 M solution?

Which from following process does NOT results in coagulation?

Calculate the number of unit cell in $1 \mathrm{~cm}^3$ volume of metal if volume of unit cell is $3.448 \times 10^{-23} \mathrm{~cm}^3$

Identify the catalyst used in following reaction at $500^{\circ} \mathrm{C}$ ?

$$ \mathrm{CO}+\mathrm{H}_2 \mathrm{O} \rightleftharpoons \mathrm{CO}_2+\mathrm{H}_2 $$