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 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

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