A solution reacts with crushed egg-shells to give a gas that turns lime-water milky.  The solution contains.

During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride.  The role of calcium chloride taken in the guard tube is to

Sodium carbonate is a basic salt because it is a salt of

If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?

Lime water is

Why do HCI, HNO₃, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic characters?

While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

How is the concentration of hydroxide ions (OH^-) affected when excess base is dissolved in a solution of sodium hydroxide?

Name the sodium compound which is used for softening hard water.

Fresh milk has a pH of 6.  When it changes into curd (yogurt) will it pH value increase or decrease? Why?

(a) What is the action on litmus of:

     (i) Dry ammonia gas

     (ii) Solution of ammonia gas in water

(b) State the observations you would make on adding ammonium hydroxide to aqueous solution of:

     (i) Ferrous sulphate

     (ii) Aluminium chloride

(i) Name the raw materials used in the manufacture of sodium carbonate by Solvay process.

(ii) How is the sodium hydrogen carbonate formed during Solvay process separated from a mixture of \(NH_4Cl\) and \(NaHCO_3\)?

(iii) How is sodium carbonate obtained from sodium hydrogen carbonate?

(i) An aqueous solution has a pH value of 7.0.  Is this solution acidic, basic or neutral?

(ii) If H+ concentration of a solution is \(1\times 10^{-2}\ mol\ L^{-1},\) what is the pH value for it?

(iii) Which has a higher pH value, 1 M HCl or 1 M NaOH solution?

Name the acid present in the following:
(i) Tomato, (ii) Vinegar, (iii) Tamarind

A liquid has a pH less than 7 which represent all acidic solution:
(i) State the nature of the solution, if its pH increases from 7 to 14.
(ii) Mention the ion whose concentration increases with the increase in pH value.
(iii) Suggest a method that is generally used for measuring the pH value.

A metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives the carbonate back.  On the other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y; it gives a compound Z, used for disinfecting drinking water.  Identity X, Y, G and Z.

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-alkali 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.

(a) Why is sulphuric acid called 'King of Chemicals'?

(b) Describe the three chemical reactions that take place during the conversion of sulphur dioxide to sulphuric aicd in the 'Contact Process'.

(c) Why should water be never added dropwise to concentrated sulphuric acid?

(i) Define universal indicator. For what purpose it is used?
(ii) Two solutions A and B have pH values of 3.0 and 9.5 respectively. Which of these will turn litmus solution from blue to red and which will turn phenolphthalein from colourless to pink?
(iii) Water is a neutral substance. What colour will you get when you add a few drops of the universal indicator to a test tube containing distilled water?