Concentration terms - molarity, molality and mole fraction — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Molarity is defined as moles of solute per

• A. litre of solution
• B. kilogram of solvent
• C. mole of solvent
• D. litre of solvent only

Question 2 · difficulty L2 · understanding

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is _______ M. (Nearest Integer value) (Given : Na = 23, I = 127, Ag = 108, N = 14, O = 16 g mol -1 )

Question 3 · difficulty L2 · understanding

Fortification of food with iron is done using $\mathrm{FeSO}_4 \cdot 7 \mathrm{H}_2 \mathrm{O}$. The mass in grams of the $\mathrm{FeSO}_4$. $7 \mathrm{H}_2 \mathrm{O}$ required to achieve 12 ppm of iron in 150 kg of wheat is ______ (Nearest integer) [Given: Molar mass of $\mathrm{Fe}, \mathrm{S}$ and and O respectively are 56, 32 and $16 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

Question 4 · difficulty L2 · understanding

The molarity of a $70 \%$ (mass/mass) aqueous solution of a monobasic acid (X) is _________ $\times 10^{-1}$ M (Nearest integer) [Given: Density of aqueous solution of (X) is $1.25 \mathrm{~g} \mathrm{~mL}^{-1}$ Molar mass of the acid is $70 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

Question 5 · difficulty L2 · understanding

20 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is _________ $\times 10^{-2} \mathrm{M}$. (Nearest integer)

Question 6 · difficulty L2 · understanding

A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ________ (Integer answer) (Given : Molar mass in $$\mathrm{g} \mathrm{~mol}^{-1}$$ Ethyl alcohol : 46 water : 18)

Question 7 · difficulty L2 · understanding

Molality of an aqueous solution of urea is $$4.44 \mathrm{~m}$$. Mole fraction of urea in solution is $$x \times 10^{-3}$$, Value of $$x$$ is ________. (Integer answer)

Question 8 · difficulty L2 · understanding

The molarity of $$1 \mathrm{~L}$$ orthophosphoric acid $$\left(\mathrm{H}_3 \mathrm{PO}_4\right)$$ having $$70 \%$$ purity by weight (specific gravity $$1.54 \mathrm{~g} \mathrm{~cm}^{-3}$$) is __________ $$\mathrm{M}$$. (Molar mass of $$\mathrm{H}_3 \mathrm{PO}_4=98 \mathrm{~g} \mathrm{~mol}^{-1}$$)

Question 9 · difficulty L2 · understanding

The mass of sodium acetate $$\left(\mathrm{CH}_3 \mathrm{COONa}\right)$$ required to prepare $$250 \mathrm{~mL}$$ of $$0.35 \mathrm{~M}$$ aqueous solution is ________ g. (Molar mass of $$\mathrm{CH}_3 \mathrm{COONa}$$ is $$82.02 \mathrm{~g} \mathrm{~mol}^{-1}$$)

Question 10 · difficulty L2 · understanding

A solution of $$\mathrm{H}_2 \mathrm{SO}_4$$ is $$31.4 \% \mathrm{H}_2 \mathrm{SO}_4$$ by mass and has a density of $$1.25 \mathrm{~g} / \mathrm{mL}$$. The molarity of the $$\mathrm{H}_2 \mathrm{SO}_4$$ solution is _________ $$\mathrm{M}$$ (nearest integer) [Given molar mass of $$\mathrm{H}_2 \mathrm{SO}_4=98 \mathrm{~g} \mathrm{~mol}^{-1}$$]