Concentrated nitric acid is 70% HNO₃. The amount of concentrated nitric acid solution that should be used to prepare 250 mL of 2.0 M HNO₃ would be:

1. 90.0 g conc. HNO₃
2. 70.0 g conc. HNO₃
3. 54.0 g conc. HNO₃
4. 45.0 g conc. HNO₃

The mole fraction of the solute in a 1.00 molal aqueous solution is: 

What is the concentration of a urea solution if 6.02×10²⁰ molecules of urea are present in 100 mL of the solution?

Which of The following has a maximum number of molecules?

1. 7g N₂ 

2. 2g H₂ 

3. 16g NO₂ 

4. 16g O₂ 

Determine the number of moles of KMnO₄ that are reduced by 1 mole of KI in an alkaline medium.

1. One-fifth 

2. Five

3. One

4. Two

Calculate the number of moles of oxygen in 1L of air containing 21% oxygen by volume, under standard conditions:

1. 0.0093 mole

2. 2.10 moles

3. 0.186 mole

4. 0.21 mole

How much oxygen gas (O₂) at standard temperature (0°C) and pressure (1 atm) is required to completely combust 1 liter of propane gas (C₃H₈) under the same conditions?

1 g of magnesium is burnt with 0.56g of oxygen in a closed vessel. The left-out reactant and its quantity are

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

Find the minimum molecular weight of the enzyme peroxidase anhydrase
 if it contains 0.5% selenium by weight.
(Atomic weight of Se = 78.4)

1. 1.568 x 10⁴ 

2. 15.68

3. 2.168 x 10⁴ 

4. 1.568 x 10³ 


 

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