[streakz]

calculate the normality and equivalent mass of oxalic acid (h2c204) if 20.00ml of oxalic acid solution reacts exactly with 39.0mg of Al(oh)3 (molar mass = 78.0g/mol)

i found that the oxalic equivalent mass is 45.0g
but the normality is 0.075.. dont know how to get that

[ssssss]

Very simple.Just use the law of equivalents.Remember Equivalents or milliequivalents react in equal number to give equal number 0f equivalents of Products.

Since 39mg of Al[OH]3 reacts completely with the amount present of [COOH]2.

So milliequivalents of [COOH]2=Milliequivalents of AL[OH]3  

Equivalent weight of Al[OH]3 is M/3

So 39/78 x 3=20xN    [Milliequivalents=NV,where v in ml]

N=0.075N

And you already have calculated the Equivalent weight of [COOH]2.Its M/2