Mole Concept

Author:Embibe Experts
JEE Main/Advance
IMPORTANT

Important Questions on Mole Concept

EASY
IMPORTANT

To a 25 ml H2O2 solution excess acidified solution of Kl was added. The iodine liberated 20 ml of 0.3 N sodium this sulphate solution. Use these data to choose the correct statements from the following :

MEDIUM
IMPORTANT

How many millilitres of 0.1 N H2SO4 solution will be required for complete reaction with a solution containing 0.125 g of pure Na2CO3 :

MEDIUM
IMPORTANT

When 1 mole of A reacts with 12mole of B2A+12B2AB100 kcal heat is liberated and when 1 mole of A reacted with 2 mole of BA+2B2AB4200 kcal heat is liberated. When of A is completely reacted with excess of Bto form AB as well as AB4, 140 kcal heat is liberated. Calculate the mole of B2 used. [Write your answer as number of mole of B2 used ×10].

MEDIUM
IMPORTANT

How many moles of magnesium phosphate, MgPO42 will contain 0.25 mole of oxygen atoms? 

EASY
IMPORTANT

21.2 g sample of impure Na2CO3 is dissolved and reacted with a solution of CaCl2, the weight of precipitate of CaCO3 is 10.0 g. Which of the following statements is/are correct? 

MEDIUM
IMPORTANT

100 g sample of clay (containing 19% H2O, 40% silica, and inert impurities as rest) is partially dried to contain 10% H2O.
Which of the following is/are correct statements (s)?

EASY
IMPORTANT

For the following reaction:

Na2CO3+2HCl2NaCl+CO2+H2O
106.0g of Na2CO3 reacts with109.5g of HCl
Which of the following is/are correct.

MEDIUM
IMPORTANT

A sample of a mixture of CaCl2 and NaCl weighing 4.44 g was treated to precipitate all the Ca as CaCO3, which was then heated and quantitatively converted to 1.12 g of CaO.

(At.wt: Ca=40,Na=23,Cl=35.5)

MEDIUM
IMPORTANT

(i) K4Fe(CN)6+3H2SO42K2SO4+FeSO4+6HCN

(ii) 6HCN+12H2O6HCOOH+6NH3

(iii) (a) 6NH3+3H2SO43NH42SO4
(b) 6HCOOHH2SO46CO+6H2O

Above steps of reactions occur in a container starting with one K4Fe(CN)6,5 mole of H2SO4 and enough water. Find out the limiting reagent in step (i) and calculate maximum moles of CO gas and NH42SO4 that can be produced.

MEDIUM
IMPORTANT

Which is/are correct statements about 1.7g of NH3:

MEDIUM
IMPORTANT

92 g mixture of CaCO3, and MgCO3 heated strongly in an open vessel. After complete decomposition of the carbonates it was found that the weight of residue left behind is 48 g. Find the mass of MgCO3 in grams in the mixture.

 

MEDIUM
IMPORTANT

If 240 g of carbon is taken in a container to convert it completely to CO2 but in industry it has been found that 280 g of CO was also formed along with CO2. Find the mole percentage yield of CO2. The reactions occurring are:

C+O2CO2;C+12O2CO

EASY
IMPORTANT

A sample of Calcium phosphate Ca3PO42 contains 8 mole of O atoms. The number of mol of Ca atoms in the sample is:

MEDIUM
IMPORTANT

How many moles of potassium chlorate need to be heated to produce 11.2 litre oxygen at N.T.P.

MEDIUM
IMPORTANT

How many liters of CO2 at STP will be formed when 0.01mol  of  H2SO4reacts with excess of Na2CO3?

Na2CO3+H2SO4Na2SO4+CO2+H2O

EASY
IMPORTANT

A sample of chalk contains clay as an impurity. The clay impurity loses 11% of its weight as moisture on prolong heating. 5 gram sample of chalk on heating shows a loss in weight (due to the evolution of CO2 and water) by 1.1g. Calculate the % of chalk CaCO3 in the sample. [Hint : Chalk CaCO3 release CO2 on heating]

MEDIUM
IMPORTANT

2g sample containing Na2CO3 and NaHCO3looses 0.248g when heated to 300°C , the temperature at which NaHCO3 decomposes to Na2CO3, CO2 and H2O. What is the percentage of Na2CO3 in the given mixture?

MEDIUM
IMPORTANT

KCIO3 decomposes by two parallel reactions,

(i2KClO3Δ2KCl+3O2  (ii4KClO3Δ3KClO4+KCl

If 3 moles of O2 and1mol of KClO4 is produced along with other products, then determine the initial moles of KClO3.

MEDIUM
IMPORTANT

The percent yield for the following reaction carried out in carbon tetrachloride CCl4 solution is 80%.

Br2+Cl22BrCl

(a) What amount of BrCl would be formed from the reaction of 0.025 mol Br2 and 0.025 mol Cl2?
(b) What amount of Br2 is left unchanged?

MEDIUM
IMPORTANT

50 g of CaCO3 is allowed to react with 73.5 g of H3PO4. Calculate the following in moles:
(i) Amount of Ca3PO42 formed
(ii) Amount of unreacted reagent