In the following sequence of reactions, the alkene affords the compound ‘B’
CH₃ - CH = CH - CH₃ $$\buildrel {{O_3}} \over \longrightarrow $$ A $$\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Zn}^{H{}_2O}} $$ B
The compound B is

The hydrocarbon which can react with sodium in liquid ammonia is

Gold numbers of protective colloids A, B, C and D are 0.50, 0.01, 0.10 and 0.005, respectively. The correct order of their protective powers is

In a compound atoms of element Y from ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be :