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Question
Calculate the percentage of boron (B) in borax (Na2B4O7.10H2O). [H = 1, B = 11, O = 16, Na = 23],
answer correct to 1 decimal place.
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Solution
Molecular mass of borax Na2B4O7.10H2O = 382
382 parts by weight of borax contain 44 parts by weight of boron
So,100 parts will contain = 44 x 100/382 = 11.5‰
Percentage of boron (B) in borax (Na2B4O7.10H2O) = 11.5‰.
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