Question

What is the Bronsted acid of H2PO4- + OH-. ---- HPO42- + H2O?​

Answer 1

Answer:

The bronsted- Lowry acid is H₂PO₄⁻

Explanation:

Bronsted-Lowry acid  donates a proton (H⁺)

H₂PO₄⁻ + OH⁻ → HPO₄²⁻ + H₂O

In the reaction above, H₂PO₄⁻ is donating the proton to OH⁻ resulting in H₂O and the deprotonated species. This makes it a bronsted-Lowry acid.

Answer 2

Answer:

$H_2 PO_4^-$ is the Bronsted acid.

Explanation:

An acid is a substance that can donate  one or more proton  

A base is a substance which can accept one or more protons

(Bronsted Acid)    +   (Bronsted Base) ---->  Conjugate Base + Conjugate acid                            

$H_2 PO_4^- + OH^-< -------- > HPO_4^{-2} + H_2 O$

Here we see  

$H_2 PO_4^-$  donates or loses $H^+$ ion to form $HPO_4^{-2}$. Hence $H_2 PO_4^-$ is the Bronsted acid (Answer)

Acid loses H+ (proton) to  forms conjugate Base $(HPO_4^{-2})$

$OH^-$ is the bronsted Base since it gains or accepts $H^+$ ion to form $H_2 O$

Base gains H+ (proton) to forms conjugate Acid $(H_2 O)$