A solution contains \(6.02\times10^{20}\) molecules of urea in 100 mL of solution. Calculate the molarity of the urea solution.
(Given: Avogadro constant, \(N_A=6.02\times10^{23}~mol^{-1}\))
1. 0.002 M
2. 0.01 M
3. 0.02 M
4. 0.1 M
To neutralize 20 mL of 0.1 M aqueous solution of phosphorus acid \((H_3PO_3) \) completely, the volume of 0.1 M aqueous KOH solution required is:
| 1. | 10 mL | 2. | 20 mL |
| 3. | 40 mL | 4. | 60 mL |
Which of the following concentration factor is affected by a change in temperature?
1. Molarity
2. Molality
3. Mole fraction
4. Weight fraction
An organic compound contains carbon, hydrogen and nitrogen in the mass ratio 9 : 1 : 3.5. If its molar mass is 108 g mol⁻¹, determine its molecular formula.
1. C6H8N2
2. C7H10N
3. C5H6N3
4. C4H18N3
The number of atoms in 560 g of Fe (atomic mass 56 g mol–1) is:
| 1. | Twice that of 70 g N |
| 2. | Half that of 20 g H |
| 3. | Both 1 and 2 |
| 4. | None of the above |
How many moles of magnesium phosphate, Mg₃(PO₄)₂, contain 0.25 moles of oxygen atoms?
| 1. | 0.02 | 2. | 3.125 × 10–2 |
| 3. | 1.25 × 10–2 | 4. | 2.5 × 10–2 |
What is the molarity of the resulting solution when 480 mL of a 1.5 M non-electrolyte solution is mixed with 520 mL of a 1.2 M solution of the same substance?
1. 2.70 M
2. 1.344 M
3. 1.50 M
4. 1.20 M
Which of the following statements is true regarding the reaction given below?
\(2 \mathrm{Al}_{(\mathrm{s})}+6 \mathrm{HCl}_{(\mathrm{aq})} \rightarrow 2 \mathrm{Al}^{3+}{ }_{(\mathrm{aq})}+6 \mathrm{Cl}^{-}_{(\mathrm{aq})}+3 \mathrm{H_2}_{\mathrm({g})}\)
| 1. | 6 L HCl(aq) is consumed for every 3L of H2(g) produced. |
| 2. | 33.6 L H2(g) is produced regardless of temperature and pressure for every mole of Al that reacts. |
| 3. | 67.2 L H2(g) at STP is produced for every mole of Al that reacts. |
| 4. | 11.2 L H2(g) at STP is produced for every mole of HCl(aq) consumed. |
The mass of potassium dichromate crystals required to oxidize 750 cm3 of 0.6 M Mohr's salt solution is:
(Given molar mass: potassium dichromate = 294, Mohr's salt = 392)
1. 0.45 g
2. 22.05 g
3. 2.2 g
4. 0.49 g
3 g of activated charcoal was added to 50 mL of acetic acid solution (0.06N) in a flask. After an hour it was filtered and the strength of the filtrate was found to be 0.042 N. The amount of acetic acid adsorbed (per gram of charcoal) is :
1. 18 mg
2. 36 mg
3. 42 mg
4. 54 mg