STD 12 - p -Block elements - ll — NEET STD 11 Science — Question

${A_2}(g) + 4{B_2}(g) \rightleftharpoons 2A{B_4}(g)\,;\,\Delta H < 0$

the formation of $AB_4(g)$ will be favoured by

$(I)$ $\phi -CH_3$

$(II)$ $\phi -CH_2-CH_3$

$(III)$ $\phi -CH(CH_3)_2$

$(IV)$ $\phi-C(CH_3)_3$

towards electrophilic substitution will be - [where $\phi =C_6H_5$]