Chemistry Class 12 NCERT Solutions: Chapter 2 Solutions Part 6 (For CBSE, ICSE, IAS, NET, NRA 2023)
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Q: 5. w/w solution of glucose in water means that of glucose in present in of the solution i.e.. , 10 g of glucose is present in of water.
Molar mass of glucose
Then, number of moles of glucose
∴ Molality of solution
Number of moles of water
Mole fraction of glucose
And, mole fraction of water
If the density of the solution is , then the volume of the solution can be given as:
∴ Molarity of the solution
Q: 6. How many mL are required to react completely with mixture of and containing equimolar amounts of both?
Ans:
Let the amount of in the mixture be x g.
Then, the amount of in the mixture is .
Molar mass of
∴ Number of moles
Molar mass of
∴ Number of moles of
According to the question,
Therefore, number of moles of
And, number of moles of
reacts with and according to the following equation.
1 mol of reacts with 2 mol of .
Therefore, mol of reacts with mol .
Similarly, 1 mol of reacts with 1 mol of .
Therefore, mol of reacts with mol of .
Total moles of required
In
is preset in 1000 mL of the solution.
Therefore, mol of is present in
of the solution
Hence, is required to react with mixture of and containing equimolar amounts of both.
Q: 7. A solution is obtained by mixing solution and solution by mass. Calculate the mass percentage of the resulting solution.
Answer:
Total amount of solute present in the mixture is given by,
Total amount of solution
Therefore, mass percentage of the solute in the resulting solution,
And, mass percentage of the solvent in the resulting solution,