Titration Methods MCQs

In Mohr’s method, the indicator used is:

• Murexide

• Potassium chromate

• Ferroin

• Starch

Answer explanation

In Mohr’s method, potassium chromate is used as the indicator because it forms a distinct color change at the endpoint of the titration, making it suitable for detecting the presence of silver ions.

Volhard’s method is a ________ type titration.

• Direct

• Back

• Complexometric

• Acid-base

Answer explanation

Volhard’s method is a back titration, where an excess of reagent is added to react with the analyte, and the unreacted reagent is then titrated. This distinguishes it from direct titrations.

Which ion is estimated in Mohr’s method?

• Sulphate

• Chloride

• Calcium

• Nitrate

Answer explanation

Mohr’s method is a titration technique used to estimate chloride ions. It involves the formation of a colored precipitate when silver nitrate is added to a solution containing chloride, confirming the presence of chloride.

The endpoint in Volhard’s titration is indicated by formation of:

• Blue color

• Red precipitate

• Reddish-brown Fe(SCN)₃ complex

• Green color

Answer explanation

In Volhard’s titration, the endpoint is indicated by the formation of a reddish-brown Fe(SCN)₃ complex, which occurs when excess thiocyanate ions react with iron(III) ions, signaling the completion of the titration.

In complexometric titration, the most commonly used titrant is:

• HCl

• KMnO₄

• EDTA

• NaOH

Answer explanation

In complexometric titration, EDTA (ethylenediaminetetraacetic acid) is the most commonly used titrant due to its ability to form stable complexes with metal ions, making it ideal for determining their concentrations.

The preferred pH for EDTA titration of Ca²⁺/Mg²⁺ is:

• 2

• 4

• 10

• 13

Answer explanation

The preferred pH for EDTA titration of Ca²⁺/Mg²⁺ is 10, as it ensures optimal complexation of metal ions, enhancing the accuracy of the titration results.

The indicator used in EDTA titration of water hardness is:

• Starch

• Potassium dichromate

• Eriochrome Black T

• Ferroin

Answer explanation

In EDTA titration for water hardness, Eriochrome Black T is the indicator used. It changes color in the presence of metal ions, allowing for the determination of hardness levels effectively.

Gravimetric analysis depends on:

• Acid-base neutralization

• Weight measurement

• pH change

• Electrical conductivity

Answer explanation

Gravimetric analysis relies on weight measurement to determine the quantity of an analyte. This method involves converting the analyte into a stable compound and measuring its mass, making 'Weight measurement' the correct choice.

In gravimetric estimation, barium is precipitated as:

• BaCl₂

• BaO

• BaSO₄

• BaCO₃

Answer explanation

In gravimetric estimation, barium is typically precipitated as barium sulfate (BaSO₄) due to its low solubility, making it an ideal choice for accurate measurement. Other options like BaCl₂ and BaO are not used for this purpose.

Redox titration involves:

• Electron transfer

• Proton exchange

• Precipitate formation

• Complexation

Answer explanation

Redox titration involves electron transfer between oxidizing and reducing agents. This process is fundamental to determining the concentration of a substance in a solution, making 'Electron transfer' the correct choice.