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A certain mass of substance in 10 g of b...

A certain mass of substance in 10 g of benzene lowers the freezing point by `1.28^(@)C` and in 100 g of water lowers the freezing point by `1.395^(@)C` separately. If the substance has normal molecular weight in benzene and completely dissociated in water, calculate number of moles of ions formed by its 1 mole dissociation in water `(K_(f_("water"))=1.86, K_(f_("benzene"))=5.00)`

Text Solution

Verified by Experts

The total number of fringes is given by `(2d)/(lambda)+1` assuming `(2d)/(lambda)` to be an integer.
`therefore (2d)/(lambda)+1= 241 implies (2d)/(lambda)= 240 implies (2d)/(lambda)= 240`
Now, let `lambda^(1)` be the changed wavelength when the YDSE set up is submerged in water.
Then the total number of fringes will be
`(2d)/(lambda)+1= (2 d mu)/(lambda)+1= 240(4/3)+1`
`(therefore mu" for water "= 4"/"3)= 321`.
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