Q107 / 270 · NDA 2025 (Phase 2) · General Ability

Match List I with List II and select the answer using the code given below the Lists:
List I (Reaction)List II (Type)
A. $CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq)$1. Single displacement
B. $CaCO_3(s) \rightarrow CaO(s) + CO_2(g)$2. Double displacement
C. $Pb(s) + CuCl_2(aq) \rightarrow PbCl_2(aq) + Cu(s)$3. Combination
D. $Na_2SO_4(aq) + BaCl_2(aq) \rightarrow BaSO_4(s) + 2NaCl(aq)$4. Decomposition

  • A
    A-2, B-1, C-4, D-3
  • B
    A-2, B-4, C-1, D-3
  • Correct answer
    C
    A-3, B-4, C-1, D-2
  • D
    A-3, B-1, C-4, D-2

Solution

Reaction A: $CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq)$ is a combination reaction because two substances combine to form a single product. (A $\rightarrow$ 3)

Reaction B: $CaCO_3(s) \rightarrow CaO(s) + CO_2(g)$ is a decomposition reaction because a single compound breaks down into two simpler substances upon heating. (B $\rightarrow$ 4)

Reaction C: $Pb(s) + CuCl_2(aq) \rightarrow PbCl_2(aq) + Cu(s)$ is a single displacement reaction because lead displaces copper from the copper chloride solution. (C $\rightarrow$ 1)

Reaction D: $Na_2SO_4(aq) + BaCl_2(aq) \rightarrow BaSO_4(s) + 2NaCl(aq)$ is a double displacement reaction because there is a mutual exchange of ions between the two reactants to form a precipitate. (D $\rightarrow$ 2)

The correct matching is A-3, B-4, C-1, D-2.

Answer: A-3, B-4, C-1, D-2

Hence, the correct answer is option: 'C'.

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