IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

Conjurer

1) 0.01 mole of H3PO2 and 0.01 moles of H3PO3 are titrated with V ml of 0.1M NaOH solution in presence of phenolphthalein indicator, V will be
a)300ml            b)200ml
c)400ml            d)500ml

2)For a given mixture of NaHCO3 and Na2CO3 volume at a given HCl required is x ml with phenolphthalein indicator and further y ml required with methyl orange indicator. Hence volume of HCl for complete reaction of NaHCO3 is
1)2x                  b)x/2
3)y                  c)(y-x)

abhishekray07

1)
eq of H3PO2 + H3PO3 = eq of NaOH
.01*1 + .01*2=(V*.1/)1000
so V=300mL

Conjurer

Moles * n factor = equivalent weight? and what is the reaction involved.How did you deduce the valence factor?

abhishekray07

moles*n factor= equivalents
H3PO2 has 1 replaceable H+ whereas H3PO3 has 2 replaceable H+

Conjurer

My question is how did you know it has 1 and 2 replaceable H+ ions respectively?

karthik2007

Read p block for that :)

abhishekray07

yaa.. you need to know the structures for that

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