Question

Match the following List - I (Type of reaction) \quad List - II (unbalanced equation) A Combination reaction \quad i) AgNO$_3$ + CaCl$_2$ $\rightarrow$ AgCl + Ca(NO$_3$)$_2$ B Decomposition reaction \quad ii) Cl$_2$ $\rightarrow$ Cl$^-$ + ClO$_3^-$ C Disproportionation reaction \quad iii) Mg + N$_2$ $\rightarrow$ Mg$_3$N$_2$ D Displacement reaction \quad iv) KClO$_3$ $\xrightarrow{\Delta$ KCl + O$_2$}

• A. A-(iii); B-(ii); C-(iv); D-(i)
  % Note: Image shows this as 1.
• B. A-(i); B-(iv); C-(ii); D-(iii)
  % Note: Image shows this as 2.
• C. A-(i); B-(ii); C-(iii); D-(iv)
  % Note: Image shows this as 3.
• D. A-(iii); B-(iv); C-(ii); D-(i) % Note: Image shows this as 4. and marked correct.

Hint:

\textbf{Combination reaction:} Two or more reactants combine to form a single product (A + B $\rightarrow$ C).
\textbf{Decomposition reaction:} A single reactant breaks down into two or more simpler products (A $\rightarrow$ B + C).
\textbf{Disproportionation reaction:} A redox reaction where an element in one oxidation state is simultaneously oxidized and reduced.
\textbf{Displacement reaction:} An atom or ion of one compound is replaced by an atom or ion of another element.
Single displacement: A + BC $\rightarrow$ AC + B.
Double displacement: AB + CD $\rightarrow$ AD + CB. (Reaction i is a double displacement).

Answer 1

The Correct Option is D

Let's analyze each reaction in List - II and match it with the type of reaction in List - I. Reaction i) AgNO$_3$ + CaCl$_2$ $\rightarrow$ AgCl + Ca(NO$_3$)$_2$ This is a double displacement reaction (also called metathesis). Two ionic compounds exchange ions to form two new compounds. Specifically, AgCl often precipitates. This is a type of displacement reaction where ions are displaced. Balanced: $2\text{AgNO}_3\text{(aq)} + \text{CaCl}_2\text{(aq)} \rightarrow 2\text{AgCl(s)} + \text{Ca(NO}_3\text{)}_2\text{(aq)}$. This matches D Displacement reaction. So, D-(i). Reaction ii) Cl$_2$ $\rightarrow$ Cl$^-$ + ClO$_3^-$ In this reaction, elemental chlorine (Cl$_2$, oxidation state 0) is converted into chloride ion (Cl$^-$, oxidation state -1) and chlorate ion (ClO$_3^-$, oxidation state of Cl is +5). Chlorine is simultaneously oxidized (0 to +5) and reduced (0 to -1). This is a disproportionation reaction. This reaction usually occurs in basic medium: $3\text{Cl}_2 + 6\text{OH}^- \rightarrow 5\text{Cl}^- + \text{ClO}_3^- + 3\text{H}_2\text{O}$. This matches C Disproportionation reaction. So, C-(ii). Reaction iii) Mg + N$_2$ $\rightarrow$ Mg$_3$N$_2$ Two elements, magnesium (Mg) and nitrogen (N$_2$), combine to form a single compound, magnesium nitride (Mg$_3$N$_2$). This is a combination reaction (also called synthesis reaction). Balanced: $3\text{Mg} + \text{N}_2 \rightarrow \text{Mg}_3\text{N}_2$. This matches A Combination reaction. So, A-(iii). Reaction iv) KClO$_3$ $\xrightarrow{\Delta$ KCl + O$_2$} A single compound, potassium chlorate (KClO$_3$), breaks down into simpler substances, potassium chloride (KCl) and oxygen (O$_2$), upon heating. This is a decomposition reaction. Balanced: $2\text{KClO}_3 \xrightarrow{\Delta} 2\text{KCl} + 3\text{O}_2$. This matches B Decomposition reaction. So, B-(iv). Summarizing the matches: A - (iii) B - (iv) C - (ii) D - (i) This set of matches corresponds to option (d). \[ \boxed{\text{A-(iii); B-(iv); C-(ii); D-(i)}} \]