How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO₃? The concentrated acid is 70% HNO₃.

1. 45.0 g conc. HNO₃

2. 90.0 g conc. HNO₃

3. 70.0 g conc. HNO₃

4. 54.0 g conc. HNO₃

Mole fraction of the solute in a 1.00 molal aqueous solution is 

1. 0.0177

2. 0.0344

3. 1.7700

4. 0.1770

6.02x10²⁰ molecules of urea are present in 100mL of its solution. The concentration of solution is 

1. 0.02M

2. 0.01M

3. 0.001M

4. 0.1M

Which has the maximum number of molecules?

1. 7g N₂ 

2. 2g H₂ 

3. 16g NO₂ 

4. 16g O₂ 

The number of moles of KMnO₄ reduced by one mole of KI in an alkaline medium is 

1. one fifth 

2. five

3. one

4. two

The number of moles of oxygen in 1L of air containing 21% oxygen by volume, under standard conditions, is 

1. 0.0093 mole

2. 2.10 moles

3. 0.186 mole

4. 0.21 mole

What volume of  oxygen gas (O₂) measured at $0°\mathrm{C}$ and 1 atm, is needed to burn completely 1L of  propane gas (C₃H₈) measured under the same conditions?

1. 7L 

2. 6L

3. 5L

4. 10L

1 g of magnesium is burnt with 0.56g of oxygen in a closed vessel. Which reactant is left in excess and how much?

(At. weight of Mg = 24, O=16)

1. Mg, 0.16g

2. O₂, 0.16g

3. Mg, 0.44g

4. O₂, 0.28g

Percentage of Se in peroxidase anhydrase enzyme is 0.5% by weight (at. weight = 78.4), then minimum molecular weight of peroxidase anhydrase enzyme is

1. 1.568 x 10³ 

2. 15.68

3. 2.168 x 10⁴ 

4. 1.568 x 10⁴ 

Number of moles of Mn${\mathrm{O}}_4^{-}$ required to oxidise one mole of ferrous oxalate completely in acidic medium will be 

1. 0.6 mole

2. 0.4 mole

3. 7.5 moles

4. 0.2 mole