Question

Sodium nitrate on reduction with $Zn$ in presence of $NaOH$ solution produces $NH_3$ Mass of sodium nitrate absorbing $1$ mole of electron will be

• A. 7.75
• B. 10.625
• C. 8
• D. 9.875

Answer 1

Answer: (B)

10.625

Answer 2

Required equation is given below,
$Zn +2 OH ^{-} \longrightarrow ZnO _{2}^{2-}+2 H ^{+}+2 e^{-}$
$NO _{3}^{-}+8 H ^{+}+8 e^{-} \longrightarrow OH ^{-}+2 H _{2} O + NH _{3}$
From the above equation
$\because 8$ moles of electron absorbed by $85\, g$ of $NaNO _{3}$
$\therefore 1$ mole of electron absorbed by $\frac{85}{8} g$ of $NaNO _{3}$
$=10.625\, g$