Ответ:

Объяснение:

Mr(KOH ) = 56

W(O) = Ar(O) *n / Mr(KOH)  *100% = 16*1 / 56  *100% =28%

W(K) = Ar(K) *n / Mr(KOH)  *100% = 39 *1 / 56 *100% = 70%

W(H) = Ar(H) *n / Mr(KOH)  *100% = 1*1 / 56  *100% =2%