Quick Answer: What Is The Difference Between A Direct Titration And A Back Titration?

What is a back titration?

Back titration is a titration done in reverse; instead of titrating the original sample, a known excess of standard reagent is added to the solution, and the excess is titrated..

What is a back titration used for?

Back titration is used in the analysis of compounds that are insoluble in water but soluble in acid. (There are other applications as well.) An excess of acid is added to the solid and the remaining acid is titrated against a standard solution of alkali.

What is back titration example?

Back titration works in the following manner (with an example) : 1: The substance or solution of unknown concentration (4 gm of contaminated chalk, CaCO3 ) is made to react with known volume and concentration of intermediate reactant solution (200 ml, 0.5N HCl). The reaction goes past the equivalence point.

How do you solve back titration problems?

5 Simple Steps in Back Titration Calculations:Determine the amount of C required in the titration.Using stoichiometry, find the amount of A that reacted with C in the titration.Note that amount of A that reacted with C in the titration = amount of A that did not react with B in the earlier reaction.More items…•Apr 24, 2019

Why is aspirin used?

Aspirin has been shown to be helpful when used daily to lower the risk of heart attack, clot-related strokes and other blood flow problems in patients who have cardiovascular disease or who have already had a heart attack or stroke. Many medical professionals prescribe aspirin for these uses.

Which titration is more accurate?

Standardization is a procedure which normalizes the titration system and provides the most accurate titrant concentration. This value is critical in the final calculation for the analyte content. If the concentration is not known precisely, it can throw off a result.

What is a back titration with antacid?

Antacids are bases that react stoichiometrically with acid. The number of moles of acid that can be neutralized by a single tablet of a commercial antacid will be determined by back titration. … The solution will be titrated with base of known concentration to determine the amount of acid not neutralized by the tablet.

Why is back titration used instead of direct titration?

A back titration is used when the molar concentration of an excess reactant is known, but the need exists to determine the strength or concentration of an analyte. … When direct titration endpoint would be hard to discern (e.g., weak acid and weak base titration) When the reaction occurs very slowly.

Why is back titration used in aspirin?

Using titration it would be difficult to identify the end point because aspirin is a weak acid and reactions may proceed slowly. Using back titration the end-point is more easily recognised in this reaction, as it is a reaction between a strong base and a strong acid.

What is the significance of boiling the solution of aspirin before titration?

In boiling the solution, aspirin is hydrolyzed into salicylic acid ad acetic acid. This liberated acids reacts with sodium hydroxide to form sodium salts.

How does titration determine purity of aspirin?

Aspirin is a weak acid that also undergoes slow hydrolysis; i.e., each aspirin molecule reacts with two hydroxide ions. To overcome this problem, a known excess amount of base is added to the sample solution and an HCl titration is carried out to determine the amount of unreacted base.

Why is back titration method used to determine the amount of CaCO3 in toothpaste instead of a direct titration?

Instead of using standard titration methods where an acid is titrated directly using a standard solution of a base, back titration is used because the sample to be analysed, CaCO3 does not dissolve in water.