pK a 1, pK a 2 and pK a 3 of H 3 PO 4 are respectively 4,8,12 respectively TK. To a 50 ml solution of 0.1 M Na 3 PO 4, 50 ml 0.2 M HCl is added. Find the pH of the mixture obtained at TK.

Question

pK a 1, pK a 2 and pK a 3 of H 3 PO 4 are respectively 4,8,12 respectively TK. To a 50 ml solution of 0.1 M Na 3 PO 4, 50 ml 0.2 M HCl is added. Find the pH of the mixture obtained at TK. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

PO 43-+2 H + longrightarrow H 2 PO 4- ∴ pH =( pK a 1+ pK a 2/2)=6

Q. $p K_{a_{1}}, p K_{a_{2}}$ and $p K_{a_{3}}$ of $H_{3} P O_{4}$ are respectively $4, 8, 12$ respectively TK. To a $50 m l$ solution of $0.1 M N a_{3} P O_{4}$ , $50 m l 0.2 M H Cl$ is added. Find the $p H$ of the mixture obtained at TK.

$P O_{4}^{3 -} + 2 H^{+} ⟶ H_{2} P O_{4}^{-}$
$∴ p H = \frac{p K _{a_{1}} + p K _{a_{2}}}{2} = 6$

Q. pKa1​​,pKa2​​ and pKa3​​ of H3​PO4​ are respectively 4,8,12 respectively TK. To a 50ml solution of 0.1MNa3​PO4​, 50ml0.2MHCl is added. Find the pH of the mixture obtained at TK.

PO43−​+2H+⟶H2​PO4−​ ∴pH=2pKa1​​+pKa2​​​=6

Q. $p K_{a_{1}}, p K_{a_{2}}$ and $p K_{a_{3}}$ of $H_{3} P O_{4}$ are respectively $4, 8, 12$ respectively TK. To a $50 m l$ solution of $0.1 M N a_{3} P O_{4}$ , $50 m l 0.2 M H Cl$ is added. Find the $p H$ of the mixture obtained at TK.

$P O_{4}^{3 -} + 2 H^{+} ⟶ H_{2} P O_{4}^{-}$
$∴ p H = \frac{p K _{a_{1}} + p K _{a_{2}}}{2} = 6$