NCERT Class XII Chemistry <br> Chapter - Solutions <br> Questions with Solutions

NCERT Class XII Chemistry
Chapter - Solutions
Questions with Solutions

Question : 26

Total: 53

If the density of some lake water is 1.25 g mL‌–1 and contains 92 g of Na‌+ ions per kg of water, calculate the molality of Na‌+ ions in the lake.

Solution:

Number of moles in 92 g of Na‌+ions
=

92 g

23 g mol−1

=4 ‌mole( as atomic mass of ‌Na=23)
As these are present in 1 kg of water, by definition molality = 4 m

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