Correct increasing order of acidity is as follows

Question

Aicharya · Accepted Answer

Such questions can be solved by considering the relative basic character of their conjugated bases which for $\mathrm{H}_{2} \mathrm{O}, \mathrm{C}_{2} \mathrm{H}_{2}, \mathrm{H}_{2} \mathrm{CO}_{3}$ and $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}$ are ${ }^{-} \mathrm{OH}, \mathrm{HC} \equiv \mathrm{C} \overline{:}, \mathrm{HCO}_{3}^{-}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}^{-}$ More the possibility for the dispersal of the negative charge, weaker will be the base. Thus the relative basic character of the four bases is

Due to resonance Thus the acidic character of the four corresponding acids will be $\mathrm{H}_{2} \mathrm{CO}_{3}>\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}>\mathrm{H}_{2} \mathrm{O}>\mathrm{HC} \equiv \mathrm{CH}$

Correct increasing order of acidity is as follows

Solution