Question

The equilibrium $\mathrm{Cr_2O_7^{2-}} \rightleftharpoons 2\mathrm{CrO_4^{2-}}$ is shifted to the right in:

• A. an acidic medium
• B. a basic medium
• C. a weakly acidic medium
• D. a neutral medium

Answer 1

Answer: (B)

a basic medium

Answer 2

The equilibrium reaction is:
$\text{Cr}_2\text{O}_7^{2-} + [\text{H}^+] + \text{OH}^- \rightleftharpoons 2\text{CrO}_4^{2-}.$
In a basic medium (OH$^-$), the reaction shifts to the right to produce more CrO$_4^{2-}$, as OH$^-$ consumes H$^+$, reducing its concentration. Conversely, in an acidic medium (H$^+$), the equilibrium shifts to the left, favoring Cr$_2$O$_7^{2-}$.
Thus, the equilibrium shifts to the right in a basic medium.