How many grams of borax ( Na ₂ ~B ₄ O ₇ .10 H ₂ O ) are required to prepare 100 mL of 0.5 M OH- solution? Atomic Mass; B=10.8 amu , O=16 amu , Na =23 amu B ₄ O ₇⁻² 4 H ₃ BO ₃+2 OH ⁻

Step-by-step solution

Mole of OH ⁻ present in 100 mL 0.5 M solution = 0.05 mole 1 mole of borax gives 2 moles of OH ⁻ 0.025 mole of borax gives 0 . 0 5 mole of OH ⁻ Weight of borax needed is 0.025 381.27=9.53 ~g