The slope of a graph $\log [A]_1$ versus ' $t$ ' for first order reaction is $-2.5 \times 10^{-3} \mathrm{~s}^{-1}$. Find rate constant of the reaction?

Identify the product formed in the following reaction.

$$ \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{MgBr} \xrightarrow[\text { ii) dil. HCl }]{\text { i) Dry ice/ dry ether }} \text { Product } $$

What is pH of weak dibasic acid, that is $2 \%$ dissociated in its M/100 solution at 298 K ?