question_answer

A metal nitrate A on heating gives yellowish brown coloured metal oxide alongwith brown gas B and a colourless gas C. Aqueous solution of A on reaction with potassium iodide forms a yellow precipitate of compound D. Identify A, B, C, D. Also identify the types of both the reactions. Metal present in A is used in alloy which is used for soldering purposes. Or (a) Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this salt. Name the source from where it is obtained. (b) What is rock salt? Mention its colour and the reason due to which it has this colour. (c) What happens when electricity is passed through brine? Write the chemical equation for it.  

Answer:

Metal nitrate A is . (I) (II)            (3) A is lead nitrate, B is nitrogen dioxide, C is oxygen and D is lead iodide.          (1) Reaction I is decomposition reaction and II is double displacement reaction (precipitation reaction).        (1) Or (a)  is acid and NaOH is base whose combination forms the common salt.                                                   (1) Its formula is NaCl (Sodium chloride). It is obtained from sea water.                                          (b) Rock salt is the common name for the mineral "halite". Its chemical formula is NaCl.                                 (1) It may be white or light blue or yellow depending upon impurities present in it.                                                 (c)