Answer 1-4 please! What is meant by \"equivalent weight\"? Predict the equivalen

Question

Answer 1-4 please! What is meant by "equivalent weight"? Predict the equivalent weight of H_3PO_4. How many equivalents arc there in one mole of oxalic acid, HOOC-COOH? Define normality. What will be the normality of a solution of Ca(OH)_2 if its molarity is 2.00 M? An unknown acid sample weighing 0.332 g was dissolved in water and then titrated with 0.08321 N NaOH. The initial buret reading for the NaOH was 0.15 mL and the final buret reading at the endpoint was 34.30 mL. What is the equivalent weight of the unknown acid?

Explanation / Answer

a)
supply or react with one mole of hydrogen cations H+ or 1 mol of OH- in an acid–base reaction.
it is weight of 1 equivalent

For H3PO4
nuumber of equivalnce = 3 since it has 3 H+
Molar mass of H3PO4= 98 g/mol

so,
equivalent weight = 98/3 = 32.7 g
Answer: 32.7 g

b)
It can give 2 H+
so number of equivalents =2

c)
Normality is defined as number of equivalance of substance dissolved in 1 L of solution
Normality = number of equivalnce * molarity
    = 2* 2M
     =4 N

d)
Use:
N1*V1 = N2*V2
1--> acid and 2 is base
N1* V1 = 0.08321 * (34.3 - 0.15)*10^-3
N1*V1=2.842*10^-3

N = mass / (equivalent weight * volume)
so,
N1 = mass / (equivalent weight * V1)
N1 *V1= mass / (equivalent weight)
2.842*10^-3 = 0.332/equivalent weight
equivalent weight=116.8 g
Answer: 116.8 g

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