Question

1g mixture of CaCO3 and Nacl reacts completely with 100ml of 0.1 N HCl .the %of CaCO3 in the mixture is 1.40% 2.60%3.50%4.80%​

Answer 1

Answer:

The correct answer is option C: 50%

Explanation:

CaCO3 reacts with HCl and forms CaCl2.

The reaction is given below.

CaCO3 + 2HCl ----------> CaCl2 +H2O + CO2

According to this equation 1 mole of CaCO3 reacts with 2 moles of HCl.

If normality of HCl is 0.1 N then its molarity is also 0.1 M.

Now calculate the number of moles:

No. of moles of HCl = 0.1M × 100mL =  0.010 mole  

For 0.010 mole of HCl 0.005 mole of CaCO3 is required to complete this reaction.

mass of CaCO3 = mole of CaCO3 × molar mass of CaCO3  

                         = 0.005 × 100

                         = 0.5g  

% of CaCO3 in mixture = 0.5/(0.5+0.5) × 100 = 50%