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Question and Answer Blog


Question.
Sir! How is wrought iron different from steel?
Answer.
Wrought Iron is the purest form of iron & is prepared from cast iron. On the other hand, Steel is an alloy of iron. Steel possesses greater tensile strength than wrought iron.

Question.
Name the method used for removing gangue from sulphide ores?
Answer.
Froth floatation method

Question.
Schottky defects lower the density of related solids.-sir not understood plz explain?
Answer.
Answer. Schottky defect is a vacancy defect which is shown by ionic solids. In this defect, an equal number of cations and anions are missing from their sites to maintain electrical neutrality. This leads to decrease in the density of a substance.

Question.
Conductivity of silicon increases on doping it with phosphorus. kindly explain?
Answer.
Silicon contains four valence electrons in its valence shell. When doped with phosphorus which is a group 15 element. Phosphorus contains five valence electrons which occupy some of the lattice sites in silicon. Four out of five electrons are used in the formation of four covalent bonds with the four silicon atoms. The fifth electron is extra and becomes delocalised. These delocalised electrons increase the conductivity of doped silicon.

Question.
which has a higher enthalpy of adsorption sir - physisorption or chemisorption?
Answer.
Chemisorption has a higher enthalpy of adsorption.

Question.
What are the products of hydrolysis of sugar?
Answer.
Sucrose & Glucose

Question.
What is meant by the term ‘forbidden zone' in reference to band theory of solids?
Answer.
It is the gap between filled valence band and the next higher unoccupied band (conduction band).

Question.
Why is the adsorption phenomenon always exothermic?
Answer.
When adsorption takes place, new bonds are formed between adsorbate & adsorbent which lowers the temperature of that substance leads to negative H value.

Question.
Although the H-bonding in hydrogen fluoride is much stronger than that in water, yet water has a much higher boiling point than hydrogen fluoride. Why?
Answer.
Hydrogen bonding of HF is stronger than water but it has lower boiling point than water because HF forms only single hydrogen bond whereas in water, it has multiple hydrogen bonds, which, when summed, have a greater intermolecular force than that of HF, leads to high boiling point.

Question.
Sir Write the full forms of DNA and RNA. Please?
Answer.
DNA- Deoxyribonucleic acid
                     RNA- Ribonucleic acid

Question.
What is meant by 'narrow spectrum antibiotics’?
Answer.
Narrow-spectrum antibiotics: - they are antibiotics which are active against a selected group of bacterial infections. For example- Penicillin G.

Question.
Sir kindly define the following terms:
                      (i) Order of a reaction
                      (ii) Activation energy of a reaction

Answer.
i). Order of a reaction: - it is the sum of the powers of the concentrations of reactants which is expressed in the rate law expression.
                    ii). Activation energy of a reaction: - it is the energy required to form an activated complex in any reaction.