The most common include: Sodium chloride (NaCl), which is used as a primary standard for silver nitrate (AgNO3) reactions. Zinc powder, which can be used to standardize EDTA (ethylenediaminetetraacetic acid) solutions after it has been dissolved in hydrochloric or sulfuric acid.

What is primary and secondary standard solution?

A primary standard is an ultrapure compound that serves as the reference material for a titration or for another type of quantitative analysis. A secondary standard is a compound whose purity has been determined by chemical analysis.

What is the primary standard in chemistry?

A primary standard is a highly pure and stable chemical reagent used to prepare standard solutions, usually for titration and making secondary standards and dilutions. In chemistry, a primary standard is a reagent that is very pure, stable, not hygroscopic, and has a high molecular weight.

How do you find the primary standard solution?

You will need to calculate:
M, the molar mass of the compound used as the primary standard M(compound) = sum of the molar mass of each element multiplied by the number of atoms present in the formula.n, the amount in moles of the compound you used as the primary standard n = m ÷ M.

What is the use of phenolphthalein?

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes.

Why can’t KMnO4 be used as a primary standard?

KMnO4 is not used as primary standard because it is difficult to obtain the pure state of KMnO4 as it is not free from MnO2. Also, the color is so intense that it acts as its own indicator.

What is secondary standard solution?

A secondary standard solution is a solution that is made specifically for a certain analysis. A secondary standard is a substance whose active agent contents have been found by comparison against a primary standard. This means it is usually standardized against a primary standard.

What is secondary standard solution example?

Example: The foundation Sodium hydroxide (NaOH) is an example of a secondary standard. Commercially available NaOH contains impurities of Sodium chloride (NaCl), Sodium carbonate (Na2CO3), and Sodium sulfate (Na2SO4), and eagerly absorbs water (H2O) from the atmosphere.

Why is HCl a secondary standard?

HCl Secondary Standard. A HCl solution is used as it can be prepared accurately and is quite stable. Because of this stability it is called a secondary standard.

Is NaOH a primary standard solution?

It is not suitable for the primary standards because they absorb the moisture from the atmosphere. It also absorbs carbon dioxide from the atmosphere. Hence, NaOH is not a primary standard because it has no quality of primary standard.

Is KMnO4 a primary standard solution?

KMnO4 is not used as primary standard because it is difficult to obtain the pure state of KMnO4 as it is not free from MnO2. Also, the colour is so intense that it acts as its own indicator.

Why primary standard is anhydrous?

Answer: Only those acids or bases areconsidered primary standard which are stable and hence their strength do not change with time. Strength ofNa2CO3 also do not change hence it isconsidered as a primary standard.

What is a primary solution?

Primary standard solutions are solutions made out of primary standard substances. A primary standard is a substance of known high purity (99.9% pure) which may be dissolved in a known volume of solvent to give a primary standard solution. Primary standards are reagents that can involve in chemical reactions.

Are all standard solution primary solution?

In analytical chemistry, a standard solution is a solution containing a precisely known concentration of an element or a substance. It is prepared using a standard substance, such as a primary standard. Standard solutions are used to determine the concentrations of other substances, such as solutions in titration.

What is the pH range of phenolphthalein?

As an indicator of a solution’s pH, phenolphthalein is colourless below pH 8.5 and attains a pink to deep red hue above pH 9.0.

What is the best pH indicator?

Perhaps the best-known pH indicator is litmus. Thymol Blue, Phenol Red, and Methyl Orange are all common acid-base indicators. Red cabbage can also be used as an acid-base indicator.

What is the pH range for methyl orange?

Detailed Solution

The pH value range where the methyl orange indicator changes its color is 3.1 – 4.4.