Question

According to Bronsted-Lowry concept of acids and bases a conjugate acid-base pair can exist as

Mark the option in which conjugate pair is not correctly matched.

	Species	Conjugate acid	Conjugate base
(a)$\,\,$	$HCO^-_3\,\,$	$CO^{2-}_3\,\,$	$H_2CO_3$
(b)$\,\,$	$HPO^{2-}_4\,\,$	$H_2PO^-_4\,\,$	$PO^{3-}_4\,\,$
(c)$\,\,$	$NH_3\,\,$	$NH^-_2\,\,$	$NH^+_4\,\,$
(d)$\,\,$	$HS^-\,\,$	$S^{2-}\,\,$	$H_2S$

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (B)

Bronsted Lowry acid base conjugate pairs differ by just one proton (acid has the extra proton). bronsted lowry acids are proton donors and bronsted lowry bases are proton acceptors. The conjugate acid of hydrogen phosphate(HP O $\left._{4}^{2-}\right)$ is $\left( H _{2} PO _{4}^{-}\right)$dihydrogen phosphate ion and the conjugate base is $\left( PO _{4}^{3-}\right)$ phosphate ion.