Name the gas formed when sodium hydroxide reacts with zinc.
Write the chemical name of baking soda.
What happens when gypsum is heated at 373K?
Which has a higher pH value 1M HCl or 1M NaOH solution?
Hydrogen ion concentration of an acid is 1 x 10-2 mol/l. what is its pH?
What is meant by ‘Water of Crystallisation’ of a substance? Describe an activity to show that.
Why does tooth decay start when the pH of mouth is lower than 5.5?
What is baking powder? How does it make the cake soft and spongy?
Give Arrhenius definition of an acid and a base. Choose strong acid and strong base from the following:
CH3COOH, NH4OH, KOH, HCl
What happens when nitric acid is added to egg shell? Give the chemical equation.
A student prepared solutions of an acid and a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?
Identify the compound ‘X’ on the basis of the reactions given below. Write the names and chemical formulae of A, B, C
+ H2 (g)
How is plaster of Paris prepared? What is its chemical formula? Write is chemical name.
Define strong acid and weak acid.
A student working in the laboratory added some water to a syrupy liquid taken in tube. The tube immediately cracked and the liquid escaped out, that produced blisters on the skin of the student. Why?
In one of the industrial process 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 reaction.
In the manufacture of sodium hydroxide, hydrogen gas and chlorine gas (X) are formed as by products. When chlorine gas (X) reacts with lime water, it forms calcium oxy chloride (bleaching powder) Y.
Dry hydrogen chloride gas does not turn blue litmus, whereas hydrochloric acid does. Why?
In the dry state, hydrogen chloride (HCl) does not release H+ ions. Therefore, it cannot behave as an acid. When dissolved in water, it forms hydrochloric acid. It dissociates to give H+ ions in solution and behaves as an acid.
Acid when react with metals release hydrogen gas but there is one acid which when reacts with metals does not release hydrogen except for two metals. Prove this statement.
Acid + Metal Salt + Hydrogen
e.g. 2HCl + 2Na 2NaCl + H2
H2SO4 + 2Na Na2SO4 + H2
HNO3 + Na No hydrogen gas.
Because nitric acid is strong oxidising agent. Nitric acid reacts only with Mg and Mn to give hydrogen gas.
Mg + 2HNO3 Mg(NO3)2 + H2
Mn + 2HNO3Mn(NO3)2 + H2
Name the properties responsible for the following uses of baling powder. (i) Baking industry (ii) As an antacid (ii) As soda-acid fire extinguisher.
What is meant by water of crystallisation of a substance? What is its importance?