Q35 / 170 · Manipal (MET) 2017 · Chemistry
Relative acidity of the following is in the order
- Correct answerA$\mathrm{RCOOH}\gt\mathrm{H}_2 \mathrm{CO}_3\gt\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\gt\mathrm{H}_2 \mathrm{O}\gt\mathrm{ROH}$
- B$\mathrm{RCOOH}\gt\mathrm{ROH}\gt\mathrm{H}_2 \mathrm{CO}_3\gt\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\gt\mathrm{H}_2 \mathrm{O}$
- C$\mathrm{ROH}\gt\mathrm{RCOOH}\gt\mathrm{H}_2 \mathrm{CO}_3\gt\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\gt\mathrm{H}_2 \mathrm{O}$
- D$\mathrm{RCOOH}\gt\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\gt\mathrm{ROH}\gt\mathrm{H}_2 \mathrm{CO}_3\gt\mathrm{H}_2 \mathrm{O}$
Solution
The order of acidity is as :
$\xrightarrow[\text { Decreasing acid strength (Decreasing } K_a \text { ) }]{R \mathrm{COOH}\gt\mathrm{H}_2 \mathrm{CO}_3\gt\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\gt\mathrm{H}_2 \mathrm{O}\gt\mathrm{ROH}}$
Hence, the correct answer is option: 'A'.