The most stable complex among the following is

For the reaction given below:
$CoCl_{3} \cdot xNH_{3} + AgNO_{3(aq)} \rightarrow$
If two equivalents of $AgCl$ precipitate out,then the value of $x$ will be $....$

Ammonia is a Lewis base. It forms complexes with cations. Which one of the following cations does not form a complex with ammonia?

The aqueous solution of a transition metal salt changes colour from pink to blue when concentrated hydrochloric acid is added to it. The change in colour is due to:

Which of the following molecules is colourless?

Assign $A, B, C, D$ from the given type of reaction:
$3KCN + Fe(CN)_3 \downarrow \longrightarrow K_3[Fe(CN)_6]$