Question

Which of the following will give a white precipitate with \( \text{AgNO}_3 \) solution?

• A. CH\(_3\)COOH
• B. NaCl
• C. C\(_2\)H\(_5\)OH
• D. Na\(_2\)CO\(_3\)

Hint:

Silver nitrate forms white precipitate with chloride ions (AgCl), cream with bromide (AgBr), and yellow with iodide (AgI).

Answer 1

The Correct Option is B

In order to determine which substance forms a white precipitate with \( \text{AgNO}_3 \), let's understand the chemical reactions involved:

1. CH\(_3\)COOH (Acetic Acid):
   Acetic acid (CH\(_3\)COOH) does not contain any halide ions such as chloride (\( \text{Cl}^- \)) that can react with \(\text{Ag}^+\) ion to form a precipitate. Therefore, it does not form a white precipitate with \(\text{AgNO}_3\).
2. NaCl (Sodium Chloride):
   Sodium chloride (NaCl) contains chloride ions (\(\text{Cl}^-\)). When these ions react with silver nitrate (\(\text{AgNO}_3\)), silver chloride (\(\text{AgCl}\)), a white precipitate, is formed:
   \[\text{Ag}^+ + \text{Cl}^- \rightarrow \text{AgCl} \, (\text{white precipitate})\]
   Thus, NaCl forms a white precipitate with \(\text{AgNO}_3\).
3. C\(_2\)H\(_5\)OH (Ethanol):
   Ethanol (\( \text{C}_2\text{H}_5\text{OH} \)) is an alcohol and does not contain halide ions, hence it does not form a white precipitate with \(\text{AgNO}_3\).
4. Na\(_2\)CO\(_3\) (Sodium Carbonate):
   While sodium carbonate can react with \(\text{AgNO}_3\), the result is not a white precipitate. Instead, it will produce silver carbonate (\(\text{Ag}_2\text{CO}_3\)), which is a different color:

Based on the reactions above, only NaCl (Sodium Chloride) will produce a white precipitate when mixed with \(\text{AgNO}_3\). Therefore, the correct answer is NaCl.