JEE Main 2021 · ChemistryNumerical answerNumerical valueHardCalculation

JEE Main 26 February 2021, Shift 2, Chemistry Q56

Question 56 of 90 in this shift, Chemistry question 26 of 30, Section B.

The pH of ammonium phosphate solution, if

pk_a

of phosphoric acid and

pk_b

of ammonium hydroxide are 5.23 and 4.75 respectively, is __________.

Official answer

NTA final key.

Chapter: Equilibrium
Topic: pH and Buffers
Idea tested: pH of Weak Acid-Weak Base Salts

Same idea in other shifts

Asked 4× in all

1 Feb 2024, Shift 1 · Q83 $\mathrm{K_a}$ for $\mathrm{CH_3COOH}$ is $1.8\times10^{-5}$ and $\mathrm{K_b}$ for $\mathrm{NH_4OH}$ is $1.8\times10^{-5}$ . The pH of…EasyNumerical value
27 Jan 2024, Shift 1 · Q63Given below are two statements : Statement (I) : Aqueous solution of ammonium carbonate is basic. Statement (II) : Acidic/basic nature of…EasyTwo statements
2 Apr 2017 (offline) · Q40 $pK_a$ of a weak acid (HA) and $pK_b$ of a weak base (BOH) are 3.2 and 3.4, respectively. The pH of their salt (AB) solution is :EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.