Page 47 - Chemistry - XI

2
M 1 25 1 M = Molarity of base = 1/20
2
1 V = Volume of base
20 V 1 2
Strength = M × Molecular weight of HCl acid _______ gL .
–1
1
Result
Strength of HCl is ____________ gL .
–1

VIVA VOCE

Q1. What is volumetric analysis?
Ans. It involves determining the quantities of a substance present in a given solution to react quantitatively
with a solution of another substance of known concentration.

Q2. What is acid-base titration?
Ans. Take fi xed volume of a base like NaOH of known concentration in a conical fl ask and add 2–3 drops
of an indicator. Then, add an acid from a burette till the pink colour disappears, it is called acid-base
titration.
Q3. Which indicator is used in titration of NaOH versus HCl?
Ans. Phenolphthalein

Q4. What is a titrant?
Ans. The solution of known strength is called a titrant.

Q5. What is a titrand?
Ans. The solution whose strength or concentration is to be determined is called a titrand.

Q6. What is titration?
Ans. Titration is a process in which fi xed volume of a solution is taken in a conical fl ask, another solution
of a known concentration is added to it with the help of a burette to bring a defi nite reaction to
completion by reacting with it.

Q7. What is a standard solution?
Ans. The solution whose concentration, i.e. molarity or normality is known is called a standard solution.

Q8. What is normality?
Ans. Normality is defi ned as number of gram equivalents dissolved per litre of solution.
Strength of solution in gL –1
N =
Equivalent weight of solute in gram
Q9. What is acidity of a base?
Ans. It is number of OH produced in an aqueous solution.
–
Q10. What is basicity of an acid?
Ans. It is the number of replaceable H present in an acid.
+
Q11. Why is the last drop of solution not blown out of a pipette?
Ans. It is because it is extra.

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