Which of the following statements are correct? (i) The rate of reactivity of alkanes with halogens is F 2 Cl 2 Br 2 I 2. (ii) Rate of replacement of hydrogens of alkanes is 3°2°1° (iii) Fluorination of alkanes is a very slow process. (iv) Iodination of alkanes is too violent to be controlled.

Question

Which of the following statements are correct? (i) The rate of reactivity of alkanes with halogens is F 2> Cl 2> Br 2> I 2. (ii) Rate of replacement of hydrogens of alkanes is 3°>2°>1° (iii) Fluorination of alkanes is a very slow process. (iv) Iodination of alkanes is too violent to be controlled. (A) (i), (ii) and (iii) (B) (i) and (ii) (C) (ii) and (iii) (D) (i) and (iv)

Tardigrade Admin · Accepted Answer

For statement (iii), fluorination is too violent to be controlled. For statement (iv), iodination is very slow and reversible reaction. It can be carried out in the presence of oxidizing agents like

H I O_{3}

or

H N O_{3}

.

C H_{4} + I_{2} ⇌ C H_{3} I + H I

5 H I + H I O_{3} \to 3 I_{2} + 3 H_{2} O

(i), (ii) and (iii)

(i) and (ii)

(ii) and (iii)

(i) and (iv)

For statement (iii), fluorination is too violent to be controlled. For statement (iv), iodination is very slow and reversible reaction. It can be carried out in the presence of oxidizing agents like HIO3​ or HNO3​. CH4​+I2​⇌CH3​I+HI 5HI+HIO3​→3I2​+3H2​O