Redox Reactions MCQs for NEET — Chemistry Questions with Answers

(C). $K_4\left[Fe{\left(CN\right)}_6\right]+K_{2}C{O}_3+5S\to Fe+C{O}_2+KCNO+5KCNS$

(C)

$SnC{l}_2 + drop by drop I_{2 }\underset{}{\to } Decolorization of Iodine SnC{l}_{2 }{I}_2$

Sn will oxidise and Hg will get reduce

(b) Cu is above Ag in electrochemical series and thus,

      $\mathrm{Cu} + 2{\mathrm{Ag}}^{+} \to {\mathrm{Cu}}^{2+} + 2\mathrm{Ag} \mathrm{reaction} \mathrm{occurs}.$

Fe being above Cu in electrochemical series and thus, liberates Cu from CuSO₄.

(b) In electrochemical series, Al is placed above Zn and all other are present below Zn. So, aluminium displaces zinc from ZnCl₂ solution. Hence, it cannot keep in contact with Al.

(c) Since copper is placed below hydrogen in the electrochemical series, thus copper does not give hydrogen with dilute acids. While all other pairs give hydrogen.

Fe + dil. H₂SO₄ → FeSO₄ + H₂ $\uparrow$

3Fe + 4H₂O → Fe₃O₄ + 4H₂ $\uparrow$

 2Na + C₂H₅OH → 2C₂H₅ONa+H₂$\uparrow$

Cu + dil.-HCl → No reaction

$$\begin{gathered} {\mathrm{Cu}}^{+2} + \mathrm{KI} \to {\mathrm{CuI}}_2 + {\mathrm{K}}^{\oplus } \\ 2{\mathrm{CuI}}_2 \to {\mathrm{Cu}}_2{\mathrm{I}}_2 + {\mathrm{I}}_2 \end{gathered}$$

whereas with Cu²⁺ + Kcl ------      CuCl2 + k⁺

(A) ${E^{\circ }}_{OP} of K > {E^{\circ }}_{OP} of Al.$

(A). Sodium reacts with water at room temperature, whereas magnesium decomposes only hot water because sodium is more electropositive than magnesium.