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Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 31 August 2021, Shift 2, Chemistry Q51

Question 51 of 90 in this shift, Chemistry question 21 of 30, Section B.

Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ ×10−1\times 10^{-1} M. (Nearest integer) [Atomic mass : Na = 23.0, O = 16.0, H = 1.0 ]

Official answer

13

NTA final key.

Same idea in other shifts

Asked 16× in all
  1. 4 Apr 2024, Shift 1 · Q61The Molarity (M) of an aqueous solution containing 5.85 g of NaCl in 500 mL water is : (Given : Molar Mass Na : 23 and Cl : 35.5…EasySingle correct
  2. 29 Jan 2024, Shift 1 · Q81A solution of H2SO4\mathrm{H_2SO_4} is 31.4% H2SO4\mathrm{H_2SO_4} by mass and has a density of 1.25g/mL. The molarity of the H2SO4\mathrm{H_2SO_4}…EasyNumerical value
  3. 30 Jan 2024, Shift 1 · Q81The mass of sodium acetate (CH3COONa\mathrm{CH_3COONa}) required to prepare 250 mL of 0.35 M aqueous solution is ________ g. (Molar mass of…EasyNumerical value
  4. 10 Apr 2023, Shift 2 · Q80Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : 3.1500g of hydrated…EasyAssertion–reason
  5. 26 Jul 2022, Shift 1 · Q85When 800 mL of 0.5 M nitric acid is heated in a beaker, its volume is reduced to half and 11.5 g of nitric acid is evaporated. The…MediumNumerical value
  6. 26 Jun 2022, Shift 1 · Q61A commercially sold conc. HCl is 35% HCl by mass. If the density of this commercial acid is 1.46 g/mL, the molarity of this solution is :…EasySingle correct
  7. 4 Aug 2021, Shift 1 · Q51A solution of H2SO4\mathrm{H_2SO_4} has 30% H2SO4\mathrm{H_2SO_4} by mass and a density of 1.25 g mL−1^{-1}. The molarity of the solution is…EasyNumerical value
  8. 26 Aug 2021, Shift 2 · Q51100 mL of Na3PO4\mathrm{Na_3PO_4} solution contains 3.45 g of sodium. The molarity of the solution is __________ ×10−2\times 10^{-2} mol…MediumNumerical value

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.