Question

Define transition elements. Write two characteristics of transition elements.

Which of the following has the highest melting point ?

Assertion (A) : The boiling points of alkyl halides decrease in the order : RI > RBr > RCl > RF. Reason (R) : The boiling points of alkyl chlorides, bromides and iodides are considerably higher than that of the hydrocarbon of comparable molecular mass.

Assertion (A) : n-Butyl chloride has higher boiling point than n-Butyl bromide. Reason (R) : C – Cl bond is more polar than C – Br bond.

Assertion (A) : The boiling points of alkyl halides decrease in the order RI > RBr > RCl > RF. Reason (R) : The van der Waals forces of attraction decrease in the order RI > RBr > RCl > RF.