Among (a) - (d), the complexes that can display geometrical isomerism are
(a) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_3 \mathrm{Cl}\right]^{+}$
(b) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right) \mathrm{Cl}_5\right]^{-}$
(c) $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}\left(\mathrm{NO}_2\right)\right]$
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Complex A has a composition of $\mathrm{H}_{12} \mathrm{O}_6 \mathrm{Cl}_3 \mathrm{Cr}$. If the complex on treatment with conc. $\mathrm{H}_2 \mathrm{SO}_4$ loses $13.5 \%$ of its original...