Question

In a closed cylinder of capacity 24.6 L the following reaction occurs at 27$^\circ$C
$A_2(s) \rightleftharpoons B_2(s) + 2C(g)$. At equilibrium 1 g of $B_2(s)$ (molar mass = 50 g mol\textsuperscript{--1}) is present. The equilibrium constant $K_p$ for the equilibrium in atm\textsuperscript{2 unit is ($R = 0.082$ L atm K\textsuperscript{--1} mol\textsuperscript{--1})}

• A. $1.6 \times 10^{-2}$
• B. $1.6 \times 10^{-5}$
• C. $1.6 \times 10^{-3}$
• D. $1.6 \times 10^{-4}$
• E. $1.6 \times 10^{-1}$

Hint:

Heterogeneous equilibrium is a favorite for examiners! Always ignore solids ($s$) and liquids ($l$) when writing $K_c$ or $K_p$ expressions—only gases ($g$) and aqueous ($aq$) species matter.

Answer 1

The Correct Option is C