Question

Match the batteries given in Column-I with the electrolytes given in Column-II. \[ \begin{array}{llcl} (a) & \text{Lead storage battery} & (r) & 38\% \text{ solution of } H_2SO_4 \\[4pt] (b) & \text{Leclanché cell} & (s) & \text{Moist paste of } NH_4Cl \text{ and } ZnCl_2 \\[4pt] (c) & \text{Mercury cell} & (p) & \text{Moist KOH} \\[4pt] (d) & \text{Nickel-Cadmium cell} & (q) & \text{KOH and ZnO paste} \end{array} \]

• A. \((a)-(r),\ (b)-(s),\ (c)-(q),\ (d)-(p)\)
• B. \((a)-(s),\ (b)-(r),\ (c)-(q),\ (d)-(p)\)
• C. \((a)-(r),\ (b)-(s),\ (c)-(p),\ (d)-(q)\)
• D. \((a)-(q),\ (b)-(p),\ (c)-(s),\ (d)-(r)\)

Hint:

Remember the commonly used electrolytes:

• Lead storage battery \(\rightarrow\) \(\mathrm{H_2SO_4}\)

• Leclanché cell \(\rightarrow\) \(\mathrm{NH_4Cl + ZnCl_2}\)

• Mercury cell \(\rightarrow\) KOH

• Nickel-Cadmium cell \(\rightarrow\) KOH + ZnO

Answer 1

The Correct Option is C

Step 1: What the question wants.
We just need to recall which liquid or paste sits inside each common battery, then read the matching off.

Step 2: Lead storage battery (a).
This is the car battery. It uses dilute sulphuric acid, about a $38\%$ solution of $H_2SO_4$. So $(a)$ goes with $(r)$.

Step 3: Leclanche cell (b).
The old dry cell uses a moist paste of $NH_4Cl$ and $ZnCl_2$ around a carbon rod. So $(b)$ goes with $(s)$.

Step 4: Mercury cell (c).
The tiny button cell used in watches uses a paste of $KOH$ and $ZnO$ as electrolyte. So $(c)$ goes with $(q)$.

Step 5: Nickel-Cadmium cell (d).
The rechargeable Ni-Cd cell works in an alkaline medium of moist $KOH$. So $(d)$ goes with $(p)$.

Step 6: Collect the pairs.
Putting it together: $(a)-(r),\ (b)-(s),\ (c)-(q),\ (d)-(p)$, which is the third option.
\[ \boxed{(a)-(r),\ (b)-(s),\ (c)-(q),\ (d)-(p)} \]