Question

5. मौखिकी
Viva-voce chemistry​

Answer 1

Question.1.What is a standard solution ?

Answer. A solution whose strength is known is called a standard solution.

Question.2.What is a normal solution ?

Answer. A solution containing one gram-equivalent mass of the solute per litre of the solution is called a normal solution.

Question.3.What is the equivalent mass of KMnO4 when it acts as oxidizing agent in acidic medium ?

Answer. KMnO4 loses 5 electrons per molecule, when it acts as oxidizing agent in the presence of acids. Therefore, its equivalent mass is one-fifth of its molecular mass.

Question.4.Is sodium hydroxide a primary standard ?

Answer. No.

Question.5.Are ‘molality’ and “molarity’’ same ?

Answer. No, molality of a solution is defined as the number of moles of solute present in 1000 grams of the solution whereas molarity tells us about the number of moles of the solute present per litre of the solution.

Question.6.What would be the normality of 0.10M KMnO4 ?

Answer. It will be 0.1 x 5 = 0.5 N.

Question.7.What volume of 10M HCl must be diluted with water to get 1L of 1M HCl ?

Answer. 0.1L.

Question.9.What is the relationship between normality (N), molarity (M), molecular mass and equivalent mass ?

Answer. Normality x Eq. Mass = Molarity x Mol. Mass.

Question.10.Why front door of the balance is closed during weighing ?

Answer. Opening the front door causes vibrations in the pan due to operator’s breath which leads to inaccurate results.