Question

A sample of hard water contains 20 mg of Ca2+ ions per litre. How manymilliequivalents of Na2CO3 would be required to soften 1 litre of the sample?

Solution

Correct option is

 

                  = 106 g

40 g Ca2+ ions react with Na2CO3 = 106 g

 ions will react with Na2CO3

                        

                        

                                            

                                    

SIMILAR QUESTIONS

Q1

Gastric juice contains about 3.0 g of HCl per litre. If a person produces about 2.5litre of gastric juice per day, how many antacid tablets each  containing 400 mg of Al(OH)­3 are needed to neutralize all the HCl produced in one day. 

Q2

What volume at N.T.P of ammonia gas will be required to be passed into 30mL of N H2SO4 solution to bring down the acid normality to 0.2 N?

Q3

The vapour density of a mixture of NO2 and N2O4 is 38.3 at 26.7oC. Calculate the number of moles of NO2 in 100 g of the mixture.

Q4

 

The mass of one litre sample of ozonised oxygen at N.T.P was found to be 1.5 g. when 100mL of this mixture at N.T.P were treated with turpentine oil, the volume was reduced to 90mL

Calculated the molecular mass of ozone. 

Q5

7.4 gram of a metal hydroxide on heating gives 5.6 g of metal oxide. Calculate the equivalent weight of the metal.

Q6

How many molecules are there in 10 litres of gas at a pressure of 75 cm at 27 degree Celsius? 

Q7

Potassium bromide, KBr contains 32.9% by mass of potassium. If 6.40 g of bromine reacts with 3.60 g of potassium, calculate the number of moles of potassium which combine with bromine to from KBr.

Q8

Two acids H2SO4 and H3PO4 are neutralized separately by the same amount of an alkali when sulphate and dihydrogen orthophosphate are formed respectively. Find the ratio of the masses of H2SO4  and 

Q9

 

10 mL of HCl solution gave 0.1435 g of AgCl when treated with excess of AgNO3. Find the normality of the acid solution

Q10

A plant virus is found to consist of uniform cylindrical particles of 150 Å in diameter and 5000 Å long. The specific volume of the virus is 0.75 cm3/ g. If the virus is considered to be a sample particle, find its molecular weight.