Question

Which of the following is a redox reaction?

पर्याय

• \[\ce{CaC2O4 + 2HCl -> CaCl2 + H2C2O4}\]

• \[\ce{Zn + 2HCl -> ZnCl2 + H2}\]

• \[\ce{NaCl + KNO3 -> NaNO3 + KCl}\]

• \[\ce{MgCO3 -> MgO + CO2}\]

Answer 1

\[\ce{Zn + 2HCl -> ZnCl2 + H2}\]

Explanation:

(A)
+2−3−2      +1−1        +2−1       +1+3−2
\[\ce{CaC2O4 + 2HCl -> CaCl2 + H2C2O4}\]

(B) \[\ce{Zn + 2HCl -> ZnCl2 + H2}\]

\[\ce{Zn -> Zn^{2+} (Oxidation)}\]

\[\ce{2H^+ -> H2 (Reduction)}\]

(C)

+1−1       +5−2        +1+5−2    +1−1
\[\ce{NaCl + KNO3 -> NaNO3 + KCl}\]

(D)

+2+4−2        +2 −2    +4−2
\[\ce{MgCO3 -> MgO + CO2}\]