Exams › JEE Main › Chemistry

A 3.0 molal NaOH solution has density 1.12 g/mL. Calculate its molarity.

1. 2.97 M
2. 3 M
3. 3.05 M
4. 3.5 M

Correct answer: 3 M

Solution

For 1 kg water, 3 mol NaOH (120 g) gives 1120 g solution; volume = 1120/1.12 = 1000 mL = 1.0 L, so molarity = 3/1.0 = 3 M.

Related JEE Main Chemistry questions

• A 100 mL sample of a urea solution contains 6.02 × 10²⁰ molecules of urea. What is the molarity of the solution? (Take Avogadro constant, N_A = 6.02 × 10²³ mol^−1.)
• When 4.9 g of H2SO4 reacts with NaCl, the products formed are 6 g of sodium hydrogen sulphate and 1.825 g of HCl. What mass of NaCl was decomposed?
• Which of the following has the least mass?
• What amount of magnesium phosphate, Mg3(PO4)2, in moles is needed to provide 0.25 mole of oxygen atoms?
• Haemoglobin has 0.33% iron by mass. If its molecular mass is about 67200 and the atomic mass of iron is 56, how many iron atoms are present in a single haemoglobin molecule?
• For the reaction 2Al(s) + 6HCl(aq) → 2Al³+(aq) + 6Cl^−(aq) + 3H₂(g), which statement is correct?

⚔️ Practice JEE Main Chemistry free + battle 1v1 →