NEET Redox Reactions PYQ practice sheet

8 previous-year NEET Chemistry questions from Redox Reactions, newest papers first. Redox Reactions carries 8 of the Chemistry questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

1. 1.

   RE-NEET 2026

   In an acidic medium, $10$ mL of $0.25$ M oxalic acid is titrated with $\mathrm{KMnO_4}$ solution. If the volume of $\mathrm{KMnO_4}$ solution required to reach end point is $10$ mL, the strength of the $\mathrm{KMnO_4}$ solution is

   • (A)
     $0.15$ M
   • (B)
     $0.20$ M
   • (C)
     $0.10$ M
   • (D)
     $0.25$ M
2. 2.

   RE-NEET 2026

   The correct decreasing order of oxidation state of the underlined atom in each molecule is

   • (A)
     $\underline{\mathrm{P}}_4\mathrm{O}_6 > \underline{\mathrm{Cl}}_2\mathrm{O}_7 > \underline{\mathrm{Al}}\mathrm{H}_3$
   • (B)
     $\underline{\mathrm{P}}_4\mathrm{O}_{10} > \underline{\mathrm{S}}\mathrm{O}_3 > \mathrm{H}_2\underline{\mathrm{O}}$
   • (C)
     $\underline{\mathrm{Pb}}\mathrm{O}_2 > \underline{\mathrm{N}}_2\mathrm{O}_3 > \underline{\mathrm{S}}\mathrm{O}_3$
   • (D)
     $\underline{\mathrm{N}}_2\mathrm{O}_5 > \underline{\mathrm{Al}}_2\mathrm{O}_3 > \mathrm{H}_2\underline{\mathrm{S}}$
3. 3.

   NEET 2024

   Which reaction is NOT a redox reaction?

   • (A)
     $\mathrm{2KClO_3+I_2\to2KIO_3+Cl_2}$
   • (B)
     $\mathrm{BaCl_2+Na_2SO_4\to BaSO_4+2NaCl}$
   • (C)
     $\mathrm{Zn+CuSO_4\to ZnSO_4+Cu}$
   • (D)
     $\mathrm{H_2+Cl_2\to2HCl}$
4. 4.

   NEET 2024

   During the preparation of Mohr's salt solution (Ferrous ammonium sulphate), which of the following acid is added to prevent hydrolysis of $\mathrm{Fe^{2+}}$ ion?

   • (A)
     dilute hydrochloric acid
   • (B)
     dilute sulphuric acid
   • (C)
     concentrated sulphuric acid
   • (D)
     dilute nitric acid
5. 5.

   NEET 2023

   On balancing the given redox reaction,

   $$a\,\mathrm{Cr_2O_7^{2-}} + b\,\mathrm{SO_3^{2-}(aq)} + c\,\mathrm{H^+(aq)} \rightarrow 2a\,\mathrm{Cr^{3+}(aq)} + b\,\mathrm{SO_4^{2-}(aq)} + \frac{c}{2}\,\mathrm{H_2O}(\ell)$$

   the coefficients a, b and c are found to be, respectively -

   • (A)
     8, 1, 3
   • (B)
     1, 3, 8
   • (C)
     3, 8, 1
   • (D)
     1, 8, 3
6. 6.

   NEET 2022

   In the neutral or faintly alkaline medium, $\mathrm{KMnO_4}$ oxidises iodide into iodate. The change in the oxidation state of manganese in this reaction is from:

   • (A)
     +6 to +5
   • (B)
     +7 to +4
   • (C)
     +6 to +4
   • (D)
     +7 to +3
7. 7.

   NEET 2021

   Which of the following reactions is the metal displacement reaction ? Choose the right option.

   • (A)
     $\mathrm{Cr_2O_3 + 2Al \xrightarrow{\Delta} Al_2O_3 + 2Cr}$
   • (B)
     $\mathrm{2KClO_3 \xrightarrow{\Delta} 2KCl + 3O_2}$
   • (C)
     $\mathrm{2Pb(NO_3)_2 \rightarrow 2PbO + 4NO_2 + O_2\uparrow}$
   • (D)
     $\mathrm{Fe + 2HCl \rightarrow FeCl_2 + H_2\uparrow}$
8. 8.

   NEET 2020

   What is the change in oxidation number of carbon in the following reaction? $\mathrm{CH_4(g) + 4Cl_2(g) \rightarrow CCl_4(l) + 4HCl(g)}$

   • (A)
     +4 to +4
   • (B)
     0 to +4
   • (C)
     -4 to +4
   • (D)
     0 to -4