Chemistry MCQs for NEET — Practice Questions with Answers

(b) Mn⁷⁺ + 5e $\to$Mn²⁺

(c) C${\mathrm{r}}_2^{6+}$ + 6e $\to$2Cr³⁺;

Cr₂${\mathrm{O}}_7^{2-}$ is reduced.

(b) Carbon has negative oxidation no. in Mg₂C₃ and positive oxidation number in C₃O₂, O  is more electronegative than C. Mg  is more electropositive than C.

(d)

fe can show +2 and +3,as its a transition element

(b) 2KClO₃ $\to$2KCl + 3O₂. An intramolecular redox change is one in which one element of a compound is oxidised (O^2- to ${\mathrm{O}}_2^{°}$) and one element is reduced (Cl⁵⁺ to Cl^1-).

(a) Fe in Fe (CO)₅ has zero oxidation no., i.e., the lowest for metals.

(d) Carbon in oxalic acid has +3 oxidation state which may be increased to +4 (in CO₂) and thus, can act as reductant. Rest all have highest oxidation number. Ox. no.of N, Mn and S in HNO₃(+5), KMnO₄(+7) and H₂SO₄(+6).

(a) The formula for Eq. mass of reductant or oxidant.

(a) 2H^- $\to$H₂ +  2e; Thus, H^- is oxidised.

(a) Fe²⁺ $\to$Fe³⁺ + e