1.0 mol of Fe reacts completely with 0.65 mol of O₂ to give a mixture of only FeO and Fe₂O₃. The mole ratio of ferrous oxide to ferric oxide is

The percentage of copper in a copper(II) salt can be determined by using a thiosulphate titration. 0.305 gm of a copper(II) salt was dissolved in water and added to, an excess of potassium iodide solution liberating iodine according to the following equation 2Cu² (aq) + 4I^– (aq) $\stackrel{}{\rightleftharpoons }$ 2CuI(s) + I₂(aq) The iodine liberated required 24.5cm³ of a 0.100 mole dm^-3 solution of sodium thiosulphate 2S₂O₃^2- (aq) + I₂(aq) $\underset{}{\overset{}{\to }}$ 2I^– (aq) + S₄O₆^2- (aq) the percentage of copper, by mass in the copper(ll) salt is. [Atomic mass of copper = 63.5]

Oxygen contains 90% O¹⁶ and 10% O¹⁸. Its atomic mass is

The total number of electrons present in 1.6 gm. of methane is [IIT 1976; Roorkee 1985; CPMT 1987, 92]

KClO₃ on heating decomposes to KCl and O₂. The volume of O₂ at STP liberated by 0.1 mole KClO₃ is

At S.T.P. the density of CCl₄ vapour in g/L will be nearest to [CBSE PMT 1988]

4.4 g of an unknown gas occupies 2.24 litres of volume at NTP. The gas may be 

The number of gram molecules of oxygen in 6.02 × 10²⁴ CO molecules are

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

The number of moles of BaCO₃ which contains 1.5 moles of oxygen atoms is [EAMCET 1991]

The oxide of metal contains 40% by mass of oxygen. The percentage of chlorine in the chloride of the metal is

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

A sample of pure compound is found to have Na = 0.0887 mole, O = 0.132 mole, C = 2.65 × 10²² atoms.

The empirical formula of the compound is 

An organic compound containing C, H and N gave the following on analysis: C = 40%, H = 13.3% and N = 46.67%. Its empirical formula would be

An organic substance containing C, H, and O gave the following percentage composition :

C = 40.687%, H = 5.085% and O = 54.228%. The vapour density of this organic substance is 59.

The molecular formula of the compound will be

When a solution containing 4.77 gm. of NaCl is added to a solution of 5.77 gm. of AgNO₃, the weight of precipitated AgCl is -

The volume of oxygen at STP required to completely burn 30 ml of acetylene at STP is

What is the volume (in litres) of oxygen at STP required for complete combustion of 32 g of CH₄

A mixture of gases contains H₂ and O₂ gases in the ratio of 1:4 (w/w). What is the molar

ratio of the two gases in the mixture?

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

would change

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide

and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate

in the sample? (Atomic weight of Mg = 24)

When 50 mL of a 16.9 %  (w/v) solution of AgNO₃ is mixed with 50 mL of 5.8% (w/v) NaCl solution, then the mass of precipitate formed is

(Ag = 107.8, N = 14, O = 16, Na= 23,Cl=35.5)

The number of water molecules is maximum in -

25.3 g of Sodium carbonate Na₂CO₃ is dissolved in enough water to make 250 mL of

solution. If sodium carbonate dissociates completely, molar concentration of sodium ion,

Na⁺ and carbonate ion ${\mathrm{CO}}_3^{2-}$ are respectively (Molar mass of Na₂CO₃ = 106 g mol^-1)

The number of atoms in 0.1 mole of a triatomic gas is 
(N_A=6.02 x10²³mol^-1)

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be:

Concentrated aqueous sulphuric acid is 98% ${\mathrm{H}}_2{\mathrm{SO}}_4$ by mass and has a density of 1.80 g mL^-1. Volume of acid required to make one litre of 0.1 M H₂S0₄ solution is :

What is the molarity of ${\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}$ solution that has a density 1.84 g/cc at $\mathbf{35}\mathbf{°}\mathbf{C}$ and contains 98% ${\mathbf{H}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}$ by weight?

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?

Which of the following contains the greatest number of nitrogen atoms ?