0 . 4g mixture of NaOH, Na _ 2 CO _ 3 and some inert impurities was first titrated with (N)/(10)HCl using phenolphthalein as an indicator, 17 . 5mL of HCl was required at the end point. After this methyl orange was

Correct answer: 0 Upto first end point gm equi. of (NaOH + Na _ 2 CO _ 3 ) = HCl x + y × 1 = (1)/(10) × 17 . 5 x + y = 1 . 75 . . . . (1) Upto second end point NaOH + Na _ 2 CO _ 3 ≡ HCl x + y × 2 = (1)/(10) × 19 x + 2y = 1 . 9 . . . . (2) y = 0 . 15 % Na _ 2 CO _ 3 = 0 . 15 × 10 ^ - 3 × 106 0 . 4 × 100 = 3 . 975 % = 4 % Hence answer is (4)

JEE Main 202125 FebruaryMorning Shift

Exam: JEE Main
Year: 2021
Date: 25 February
Shift: Morning Shift
Subject: Chemistry
Chapter: Redox Reactions

JEE Main 2021 · 25 February · Morning Shift · Chemistry · Redox Reactions

0 . 4g mixture of NaOH, Na _ 2 CO _ 3 and some inert impurities was...

0 . 4g

mixture of

NaOH, {Na}_{2}{CO}_{3}

and some inert impurities was first titrated with

\dfrac{N}{10}HCl

using phenolphthalein as an indicator,

17 . 5mL

HCl

was required at the end point. After this methyl orange was added and titrated.

1 . 5mL

of same

HCl

was required for the next end point. The weight percentage of

{Na}_{2}{CO}_{3}

in the mixture is (Rounded-off to the nearest integer)

Correct answer

Step-by-step solution

Upto first end point gm equi. of $\left(NaOH + {Na}_{2}{CO}_{3}\right) = HCl$

$x + y \times 1 = \dfrac{1}{10} \times 17 . 5$

$x + y = 1 . 75 . . . . \left(1\right)Upto second end point$ NaOH + {Na}_{2}{CO}_{3} ≡ HCl $$ x + y \times 2 = $\dfrac{1}{10}$ \times 19 $$ x + 2y = 1 . 9 . . . . \left(2\right) $$ y = 0 . 15 $$ % {Na}_{2}{CO}_{3} = \dfrac{0 . 15 \times {10}^{- 3} \times 106}{0 . 4} \times 100 $$ = 3 . 975 % $$ = 4 % $Hence answer is \left(4\right)$

Practice Redox Reactions on Quantrex Academy →

More from Redox Reactions

500 mL of 0.2 M MnO _4^- solution in basic medium when mixed with 500 mL of 1.5 M KI… JEE Main 2026 Given below are two statements: Statement I: Sodium dichromate and potassium dichromate… JEE Main 2026 In order to oxidise a mixture of 1 mole each of FeC_2O_4 , Fe_2(C_2O_4)_3 , FeSO_4 and… JEE Main 2026 500 mL of 1.2 M KI solution is mixed with 500 mL of 0.2 M KMnO_ 4 solution in basic… JEE Main 2026 One mole of Cl_ 2 (~g) was passed into 2 L of cold 2 M KOH solution. After the reaction… JEE Main 2026 X and Y are the number of electrons involved, respectively during the oxidation of I^… JEE Main 2026 200 cc of x × 10^ -3 M potassium dichromate is required to oxidise 750 cc of 0.6 M Mohr's… JEE Main 2026 Identify the correct statements : A. Hydrated salts can be used as primary standard. B.… JEE Main 2026 Full Redox Reactions list All JEE Main PYQs