Question

For the complex, $A{g}^{+}+2N{H}_3\to \left[Ag\right(N{H}_3{)}_2^{+}]$,

$\left(\frac{dx}{dt}\right)=2\times {10}^7{L}^{2}mo{l}^{-2}{s}^{-1}\left[A{g}^{+}\right][N{H}_3{]}^2=1\times {10}^{-2}{s}^{-1}[Ag\left(N{H}_3{)}_2^{+}\right]$.

Hence, the ratio of rate constants of the forward and backward reactions is:

• A. $2\times {10}^7$ $L^2$ $mo{l}^{-2}$
• B. $2\times {10}^9$ $L^2$ $mo{l}^{-2}$
• C. $1\times {10}^{-2}$ $L^2$ $mo{l}^{-2}$
• D. $0.5\times {10}^{-9}$ $L^2$ $mo{l}^{-2}$

Answer 1

The correct option is B $2\times {10}^9$ $L^2$ $mo{l}^{-2}$

$r_f=2\times {10}^7\left[A{g}^{+}\right][N{H}_3{]}^2$

$K_f\left[A{g}^{+}\right][N{H}_3{]}^2=2\times {10}^7[A{g}^{+}\left]\right[N{H}_3{]}^2$

$K_f=2\times {10}^7$

$r_b=1\times {10}^{-2}\left[Ag\right(N{H}_3{)}_2^{+}]$

$\therefore K_b=1\times {10}^{-2}$

$\frac{K_f}{K_b}=\frac{2\times {10}^7}{1\times {10}^{-2}}=2\times {10}^9{M}^{-2}$