An isomer of $\mathrm{C}_5 \mathrm{H}_{12}$ on reaction with $\mathrm{Br}_2$ /light gave only one isomer $\mathrm{C}_5 \mathrm{H}_{11} \mathrm{Br}(X)$. Reaction of $X$ with $\mathrm{AgNO}_2$ gave $Y$ as major product. What is $Y$ ?

What are the major products $X$ and $Y$ respectively in the following reactions?

$$ \begin{aligned} & \left(\mathrm{CH}_3\right)_3 \mathrm{CONa}+\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Br} \longrightarrow X \\ & \left(\mathrm{CH}_3\right)_3 \mathrm{CBr}+\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{ONa} \longrightarrow Y \end{aligned} $$