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Some Basic Concepts Of Chemistry

Question
CBSEENCH11005091

Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction,
 CaCO subscript 3 left parenthesis straight s right parenthesis space plus space 2 HCl space left parenthesis aq right parenthesis space rightwards arrow space space CaCl subscript 2 left parenthesis aq right parenthesis space plus space CO subscript 2 left parenthesis straight g right parenthesis space plus space straight H subscript 2 straight O left parenthesis straight l right parenthesis

What mass of CaCO3 is required to react completely with 25 mL of 0·75M HCl?

Solution
1000 mL of HCl contains 0·75 mol
                                 = 0.75 x 36.5
                                 = 27.375 g
therefore   25 mL of HCl contains equals space fraction numerator 27.375 over denominator 1000 end fraction cross times 25
                                        = 0.684 g
The reaction is
CaCO3(s)    +   2HCl(aq) rightwards arrow   CaCl2(aq) + CO2(g) + H2O(l)
1 mol                 2 mol
40+12+48          2 x 36.5
 = 100 g              = 73 g
?                        0.684 g
    Now 73 g of HCl are required to react with 100g of CaCO3
therefore     
0.684 g of HCl are required to react with
100 over 73 cross times 0.684 space straight g space of space CaCO subscript 3 space equals space 0.94 space straight g space CaCO subscript 3