(i) Why could fluorine not be prepared for a long time from HF and metal fluorides either by electrolysis or by any chemical reaction ?
(ii) Describe the modern method for the preparation of fluorine by giving:
(a) Materials used in the construction of the cell.
(b) Electrolyte used.
(c) Electrode reactions.

(A) Complete the following chemical reactions: (i) XeF_(4)+SbF_(5)to (ii) XeF_(6)+2H_(2)O to (iii) XeF_(6)+3H_(2)O to (B) Why could fluorine not be prepared for a long time from HF and metal fluorides either by electrolysis or by any chemical reaction ?

(a) Fluorine cannot be prepared from fluorides by chemical oxidation. Why? (b) Anhydrous HCl is bad conductor of electricity while aqueous HCl is a good conductor.

Hydrogen chloride gas is prepared in the laboratory using concentrated sulphuric acid and sodium chloride. Answer the question that follow based on this reaction : Give the balanced chemical equation for the reaction with suitable conditions(s) if any.

(a) Which will adsorb more gas, a lump of charcoal or its powder and why? (b) Describe the preparation of the following colloidal solutions. Name the method used in each case: (i) Silver sol (ii) Sulphur sol

(i) Identity the products A,B and C: . (ii) Starting with Grignard.s reagent, how will you prepare propanoic acid ? (iii) Give balanced equation for the following name reaction : Kolbe.s electrolytic reaction.

(a) Name the method of refining which is (i) used to obtain semiconductor of high purity (ii) used to obtain low boiling metal. (b) Write chemical reactions taking place in the extraction of copper from Cu_(2)S .

(a) Name the starting material used in the industrial preparation of phenol. (b) Write complete reaction for the bromination of phenol in aqueous and non-aqueous medium. (c) Explain why Lewis acid is not required in bromination of phenol ?

A chemical reaction may b reversible in nature. State the meaning of the term in italics. Give a reason why a catalyst is used in certain chemical reactions. Give a balanced equation for the following - a. A reversible catalytic reaction involving- i. nitrogen as one of the reactants ii. Sulphur dioxide as one of the reactants.

The elements of group II are known as alkaline earth metals. The electronic configuration of these elements is ns^(2) and oxidation state is +2 . They have higher ionization energy than alkali metals in their respective period due to their small size and completely filled s-orbital. These elements give characteristic colour to bunsen flame. magnesium is used in the preparation of Grignard agent (RMgX) which is used in organic chemistry for preparation of sevaral organic compounds like alcohols. acids, hydrocarbons. Q. The reaction of RMgX with water will produces

Give balanced chemical eqauations for - i] Lab preparation of ammonia using an ammonium salt. (ii) Reaction of ammonia with excess chlorine .iii] Reaction of ammonia with sulphuric acid.