4.4 g of an unknown gas occupies 2.24 litres of volume at NTP. The gas may be [MP PMT 1995]

(1) Carbon dioxide

(2) Carbon monoxide

(3) Oxygen

(4) Sulphur dioxide

The mass of carbon present in 0.5 mole of K₄[Fe(CN)₆] is:

The number of moles of oxygen in one litre of air containing 21% oxygen by volume under standard conditions is [CBSE PMT 1995]

(1) 0.186 mole

(2) 0.21 mole

(3) 0.0093 mole

(4) 2.10 mole

The empirical formula of an organic compound containing carbon and hydrogen is CH₂. The mass of one litre of this organic gas is exactly equal to that of one litre of N₂. Therefore, the molecular formula of the organic gas is

(1) C₂H₄

(2) C₃H₆

(3) C₆H₁₂

(4) C₄H₈

An organic compound containing C, H and N gave the following on analysis: C = 40%, H = 13.3% and N = 46.67%. It's empirical formula would be [CBSE PMT 1999, 2002]

(1) CHN

(2) C₂H₂N

(3) CH₄N

(4) C₂H₇N

The volume of oxygen at STP required to completely burn 30 ml of acetylene at STP is [Orissa JEE 1997]

(1) 100 ml

(2) 75 ml

(3) 50 ml

(4) 25 ml

If Avogadro number N_A, is changed from 6.022 x 10²³ mol^-1 to 6.022 x 10²⁰ mol^-1 this would change

(1) the definition of mass in units of grams

(2) the mass of one mole of carbon

(3) the ratio of chemical species to each other in a balanced equation

(4) the ratio of elements to each other in a compound

6.02 x 10²⁰ molecules of urea are present in 100 mL of its solution. The concentration of the solution is

(a) 0.02 M

(b) 0.01 M

(c) 0.001 M

(d) 0.1 M

A mixture of methane and ethene in the molar ratio of x : y has a mean molar mass of 20. What would be the mean molar mass. if the gases are mixed in the molar ratio of y : x?

(1) 22                               

(2) 24

(3) 20.8                           

(4) 19

The volume of a drop of water is 0.0018 mL then the number of water molecules present in two drop of water at room temperature is:

1.  $12.046\times {10}^{19}$

2.  $1.084\times {10}^{18}$

3.  $4.84\times {10}^{17}$

4.  $6.023\times {10}^{23}$