Chemistry · Acids, Bases and Salts
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Which one of the following salts will produce an alkaline solution when dissolved in water?
- A
NH4Cl
- B
NaNO3
- C
Na2CO3
- D
Na2SO4
The correct answer is Na2CO3. Sodium carbonate forms an alkaline solution because it undergoes hydrolysis in water, releasing hydroxide ions (OH-) which increase the pH. In contrast:
- NH4Cl forms an acidic solution due to ammonium ions generating hydronium ions.
- NaNO3 remains neutral as neither ion affects pH significantly.
- Na2SO4 also results in a neutral solution for similar reasons to NaNO3.
NH4Cl (Ammonium chloride) is an acidic salt. When dissolved in water, it releases ammonium ions (NH4+), which slightly acidify the solution by forming hydronium ions (H3O+).
NaNO3 (Sodium nitrate) is a neutral salt. Its dissolution in water does not affect the pH significantly, as neither sodium ions (Na+) nor nitrate ions (NO3-) react with water to alter the pH.
Na2CO3 (Sodium carbonate) forms an alkaline solution upon dissolution. It undergoes hydrolysis to produce hydroxide ions (OH-), increasing the pH and making the solution alkaline.
Na2SO4 (Sodium sulfate) is a neutral salt. Neither its sodium ions (Na+) nor sulfate ions (SO42-) significantly interact with water, resulting in a neutral solution.
Tagged under Chemistry · Acids, Bases and Salts · 2013