Question

Which of the following property/ properties of sand is used for a sand bath during roasting?
A.High thermal capacity
B.Non-combustible
C.Both A and B
D.Combustible

Answer 1

 Hint:A sand bath is an apparatus commonly used in chemical laboratories and it is made up from a container filled with heated sand. The main application of sand bath is to provide even heating to another container during a chemical reaction.


Complete step by step answer:
-In sand bath technique, a hot plate is used in conjunction with the sand bath. A beaker filled with sand is then placed on the hot plate and the reaction vessel is partially covered with sand. The sand then conducts heat from the hot plate to the reaction vessel uniformly on all sides.
-The sand bath heating method makes it possible for the reaction vessel to be heated with minimum stirring as it involves indirect heating and heat is supplied to all sides, as compared to the chemical reactions where the reaction vessel is heated directly. Thus, sand bath take a very less amount of time and the possibilities of side reactions occurring at high temperatures are removed. All this is possible due to the high thermal capacity of the sand used in the sand bath. So, option A is correct.
-Also, the process of roasting involves the heating of a sulphide ore to metal oxide in presence of air. Since sand does not burn in air and catch fire easily, it is highly useful for the sand bath used in roasting. Thus, sand is also non-combustible. Hence, option B is also correct.

Hence, the correct option is C.


Note:
An alternative heating technique to sand bath is the water bath. Here, the sand is replaced with water and this technique is useful for keeping reaction vessels at the temperature of boiling water over a long period of time.