A compound ‘A’ is used in fire extinguishers, as an antacid and its small amount is also used in making bakery items. Identify the compound and also explain the reason for above mentioned uses of the compound ‘A’. Open Answer »
A dry pellet of a common base B, when kept in open absorbs moisture and turns sticky. The compound is also a by-product of chlor-al kali process. Identify B. What type of reaction occurs when B is treated with an acidic oxide? Write a balanced chemical equation for one such solution. Open Answer »
A baker found that the cake prepared by him is hard and small in size. Which ingredient had he forgotten to add that would have caused the cake to rise and become light? Give reason. Open Answer »
In one of the industrial processes used for manufacture of sodium hydroxide, a gas X is formed as by-product. The gas X reacts with lime water to give a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y giving the chemical equation of the reactions involved. Open Answer »
Why is acetic acid called a weak acid though there are four hydrogen atoms in the molecule? Open Answer »
A student accidently spilled concentrated H2SO4 on his hand. Before the teacher got to know, his friend washed his hands with water and also with soap but the burning sensation on hand still continued. His friend then rubbed solid sodium bicarbonate on his hand and then washed with water, finally the burning sensation is relieved. Answer the following questions based on the above situation (i) Mention the values shown by student’s friend. (ii) Can you recommend any other substance available in the laboratory which can be used instead of sodium bicarbonate? (iii) Write the chemical reaction involved in the treatment of acid burn with sodium bicarbonate. Open Answer »
Farmers are using a large number of pesticides and fertilisers in their fields to increase crop production and to enhance their profits. But by doing so, they are causing damage to the soil as well as to the environment. Answer the following questions based on the above situation: (i) Do you agree with this statement? (ii) Why should we avoid eating fruits and vegetables without washing them properly? (iii) What values are neglected by the farmers? Open Answer »
Nishant is a lazy boy. He doesn’t like to brush his teeth instead he rinses his mouth with water. His mother makes sure that he brushes his teeth twice a day. Answer the following questions based on the above situation: (i) Why does Nishant’s mother insist on brushing teeth twice a day? (i) How is a toothpaste better than just water, for cleaning teeth? (ii) What values are promoted by Nishant’s mother? Open Answer »
A sulphate salt of group 2 element of the periodic Table is a white, soft substance, which can be moulded into different shapes by making its dough. When this compound is left in open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt and state why does it shows such a behaviour. Give the reaction involved. Open Answer »
Write the formulae of the salts given below. Potassium sulphate, sodium sulphate calcium sulphate, magnesium sulphate, copper sulphate, sodium chloride sodium nitrate, sodium carbonate and ammonium chloride. Identify the acids and bases from which the above salts may be obtained. How many families can you identify among these salts? Open Answer »
