1.

Borax in water gives `B_(4)O_(7)^(2-)+7H_(2)O rarr 4H_(3)BO_(3)+2OH^(-)` How many grams of Borax `(Na_(2)B_(4)O_(7). 10H_(2)O)` are required to prepare 50 ml of 0.2 M solution.A. (a)0.32 gB. (b)3.82 gC. (c )0.28 gD. (d)None of these

Answer» Correct Answer - b
The n-factor or valency factor of borax in the above reaction is 2
Meq. Of borax in 50 ml solution `=50xx0.2xx2=20`
Let weight of borax required =W
`W/382xx2xx1000=20`
`:. W_((Na_(2)B_(4)O_(7). 10H_(2)O))=3.82`


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