Monday, March 13, 2023

Normality Numerical

Normality NumericalMolarityMolarity (M) is defined as the number of moles of a solute present in per litreof solution.i.e. Molarity = Number of moles of solute
Volume of solution in liter
No of moles = mass
molecular weight
Molar solution: The solution containing one mole of solute in one litre solutionis called molar solution. For example, if one mole of nitric acid (63 gram) ispresent in one litre of solution, it is called molar solution. Decimolar solution: The solution containing 1/10 mole of a solute in one litresolution is called deci molar solution. For example, if 1/10 mole of nitric acid (6.3gram) is present in one litre of solution, it is called decimolar solution. MolalityMolality (m) is defined as the number of moles of solute present in one kilogramof solvent.i.e. Molality = Number of moles of solute
Mass of of solvent in kilogram
Example 1Calculate the molarity of 40g H2SO4 in 200ml solution.Solution:Given, mass of solute =40gVolume of solution =200mlWe know that molar mass of H2SO4=98gAgain, number of moles of H2SO4= Mass of solute
Molecular weight of solute
=40g
98g
=40
98
Also, volume of solution in litres =200
1000
=1
5
Now, Molarity (M)= moles of solute
litres of solution
=40/98
1/5
=2.04M
Example: 2Calculate the molality if 90g of NaCl is added into 1800 grams of water.Solution:Given, mass of solute =90gMass of solvent =1800gWe know that molar mass of NaCl=58g (approx)Number of moles of NaCl= Mass of solute
Molecular weight of solute
=90g
58g
Mass of solvent in kg=1800
1000
=9
5
Now, Molality (M)= Moles of solute
Mass of solvent in kg
=90/58
9/5
=0.86M
Normal solution (1N)The solution containing one equivalent of solute in one litre of solution is called normal solution. Equivalent mass of acid = Molar mass of acid
Basicity
(Here, basicity means number of replaceable hydrogens)
Equivalent mass of base = Molar mass of base
Acidity
(Here, acidity means the number of replaceable hydroxyl ions)
Normality = n × M where n= n factor (basicity or acidity) M = molarity
For example, if 36.5g of hydrochloric acid (one equivalent) is present in one litre of solution, then it is called normal solution of HCl. if 49g of sulphuric acid (one equivalent) is present in one litre of solution, then it is called normal solution of sulphuric acid. Decinormal solution (N/10) The solution containing 1/10 equivalent of solute in one litre of solution is called decinormal solution. For example, if 3.65g of hydrochloric acid (N/10 equivalent) is present in one litre of solution, then it is called decinormal solution of HCl. if 4.9g of sulphuric acid (N/10 equivalent) is present in one litre of solution, then it is called decinormal solution of sulphuric acid. Calculate the normality of the following.a. 4 M of H2SO4.b. 12.5g of calcium carbonate in 200ml of solution a. Solution:Given, Molarity of the solution (M)=4n factor of H2SO4=2As we know, Normality (N)=n×M=2×4=8 b. Given, Mass of solute =12.5gMolar mass of calcium carbonate =100g"n" factor of calcium carbonate =2Solution =200mlEquivalent mass of calcium carbonate = Molar mass
"n" factor
=100
2
=50
Normality (N)= Mass of solute in gram
Equivalent mass
×1000
Volume of solution in ml
Normality (N)=12.5
50
×1000
200
Normality (N)=1.25N

No comments:

Post a Comment

Featured Post

Wave simulation