Thermal decomposition of a Mn compound (X) at 513 K results in compound Y, MnO₂ and gaseous product. MnO₂ reacts with NaCl and concentrated H₂O₄ to give a pungent gas Z. X, Y and Z, respectively, are :

Which one of the following is likely to give a precipitate with AgNO₃ solution ?

In which one of the following equilibria, K_p $$ \ne $$ K_C ?

Benzene diazonium chloride on reaction with aniline in the presence of dilute hydrochloric acid gives :