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]]>The principle of acid & base titration is based on neutralization reaction which occur between acid and base.
ACID + BASE ⇒ SALT + WATER
Phenolphthalein is the most commonly used indicator for acid base titration.
According to arrhenius an acid is any substance which is capable of providing hydrogen ions in aqueous solutions and base is defined as a substance containing hydroxy group and/ or capable of providing hydroxide ions in aqueous solutions.
HA + BOH → B+ A–+ H2O
(ACID) (BASE) (SALT) (WATER)
In Arrhenius acid base reaction a salt and water is formed from the reaction between an acid and a base. In other words this is a neutralization reaction.
H2SO4 + NaOH → Na2SO4 + 2H2O
This concept is based upon the idea of protonation of bases through deprotonation of acids. According to this concept acid and base can be defined as :-
ACIDS :- Is any substance capable of donating a proton (H+) in a chemical reaction.
BASE :- Is any substance capable of accepting a proton (H+) in a chemical reaction.
SO2 + SO2 ⇒ SO+2 + SO3-2
Thus the protonic definition cannot be used to explained the reaction occuring in non-protonic solvents such as COCl2,SO2, etc.
Any substance which can accept a share in a pair of electrons in a reaction is called an acid and a base is any substance which can donate a pair of electrons to share with an acid in a reaction.
The lewis concept have some limitations these are :-
A+B ⇔ C+D
K = [C][D]/[A][B]
Where K = Equilibrium constant of the reaction.
MCQ
1.What is a Equivalence point ?
a. Amount of titrant = Amount of analyte in a sample.
b.Amount of titrant > Amount of analyte in a sample.
c.Amount of titrant < Amount of analyte in a sample.
d. None of the above
2. According to arrhenius concept which sentence is true ?
a. Proton acceptor is base.
b.Electron pair acceptor is acid.
c. Electron pair donor is base.
d. Hydroxide donor is base.
3. What is law of mass action ?
a.The rate of a chemical reaction is proportional to the active masses of the reacting substance.
b.The rate of a chemical reaction is inversely proportional to the active masses of the reacting substance.
c.a and b
d. None of the above
4.what is titrant ?
a. A solutions of one reactant of accurately known concentration.
b. A solutions of one reactant of unknown concentration.
c. a and b
d. none of the above
5. According to lewi’s concept which sentence is true ?
a.Proton donor is acid.
b. Proton acceptor is base.
c.Hydroxide donor is base.
d. Electron pair acceptor is acid.
6.What is principle of acid base titration ?
a. Neturalization
b. Alkalimetry
c. a and b
d.None of the above
7. Which is not limitation of arrhenius concept ?
a. The theory is not able to explain acidic and basic properties of substance in non aqueous solvent eg,NH4NO3 in liquid NH3 acts as an acid though it dose not give H+ions.
b.It cannot explained the acidic character of certain salts such as ALCL3 in aqueous solutions.
c.The definition of acid and base are only in term of aqueous solutions and not in terms of substance.
d. Proton donor is acid.
8.What is the end point ?
a.Physical change occurs which related to the chemical change.
b.A reagent of a known concentration which used in the titrimetric analysis.
c.A solutions of one reactant of accurately known concentration.
d. Amount of titrant = Amount of analyte in a sample.
ANSWER KEY
1.A
2.D
3.A
4.A
5.D
6.A
7.D
8.A
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REFERENCE :-
VOGEL′S TEXT BOOK OF QUANTITATIVE CHEMICAL ANALYSIS FIFTH EDITION BY G.H.JEFERY, J.BASSETT (PG.NO. 262-268)
The post ACID-BASE TITRATION: Principle, Theory, Limitations and MCQ for GPAT, GATE and CSIR NET JRF appeared first on Gpatindia: Pharmacy Jobs, Admissions, Scholarships, Conference,Grants, Exam Alerts.
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