Q.1. What is the change in oxidation number of carbon in the following reaction? (2020)
CH4(g) + 4Cl2(g) → CCl4(l) + 4HCl(g)
(a) -4 to +4
(b) 0 to -4
(c) +4 to +4
(d) 0 to +4
Q.2. Which of the following reactions are disproportionation reaction? (2019)
(a) 2Cu+ → Cu2+ + Cu
Select the correct option from the following
A: (a) and (b) only
B: (a), (b) and (c)
C: (a), (c) and (d)
D: (a) and (d) only
Disproportionation reaction: The reaction in which same element/compound get oxidized and reduced simultaneously.
Q.3. The correct structure of tribromooctaoxide is (2019)
The correct structure is
Q.4. The correct order of N-compounds in its decreasing order of oxidation states is (2018)
A: HNO3, NO, N2, NH4Cl
B: HNO3, NO, NH4Cl, N2
C: HNO3, NH4Cl, NO, N2
D: NH4Cl, N2, NO, HNO3
Q.5. For the redox reaction
MnO4– + C2O42–+ H+ →Mn2+ + CO2 + H2O
the correct coefficients of the reactants for the balanced equation are (2018)
MnO4– C2O4 2– H+
(1) 16 5 2
(2) 2 5 16
(3) 2 16 5
(4) 5 16 2
Q.6. The pair of compounds that can exist together is : (2014)
A: HgCl2 ,SnCl2
B: FeCl2 ,KI
D: FeCl2 ,SnCl2
The compounds with lower oxidation number and which cannot reduce by one another can exist together. Thus, FeCl2 and SnCl2 can exist together as Fe2+ can not be reduced by Sn2+.
Q.7. In acidic medium H2O2 changes Cr2O7 to CrO5 which has two −O−O− bonds. Oxidation state of Cr in CrO5 is : (2014)
CrO5 has butterfly structure having two peroxo bonds.
Peroxo oxygen has -1 oxidation state.
Let oxidation state of Cr be 'x'
CrO5 : x + 4(-1) + 1 (-2) = 0 ⇒ x = + 6