Find the total number of compounds/ions having linear shape.

${\left[\mathrm{Ag}(\mathrm{CN}{)}_2\right]}^{-},{\mathrm{HgCl}}_2,{\mathrm{SnCl}}_2,{\mathrm{NO}}_2^{+},{\mathrm{ClO}}_2^{+},{\mathrm{AuCl}}_2^{-}$

The compounds which have the linear shape from the given options are,

${\left[\mathrm{Ag}(\mathrm{CN}{)}_2\right]}^{-},{\mathrm{NO}}_2^{+},{\mathrm{AuCl}}_2^{-},{\mathrm{HgCl}}_2$

Here,${\mathrm{NO}}_2^{+}$ is linear as it contain sp hybridization and does not contain any lone pairs.

Hence correct answer is 0004