Modern Periodic Table and Periodic Properties — Chemistry STD 10 — Question

What do you understand by redox reactions? Explain oxidation and reduction in terms of loss or gain of electrons.

How does tooth enamel get damaged? What should be done to prevent it?

(a) Name the gas evolved when the following mixtures are heated :
(i) Calcium hydroxide and ammonium chloride
(ii) Sodium nitrite and ammonium chloride
(b) Write balanced chemical equations for each of the following :
(i) When excess of ammonia is treated with chlorine.
(ii) An equation to illustrate the reducing nature of ammonia.

The following is a list of methods for the preparation of salts.
A – direct combination of two elements
B – reaction of a dilute acid with a metal.
C – reaction of a dilute acid with an insoluble base.
D – titration of a dilute acid with a solution of soluble base.
E – reaction of two solutions of salts to form a precipitate.
Choose from the above list A to E, the best method of preparing the following salts by giving a suitable equation in each case:
1. Anhydrous ferric chloride,
2. Lead chloride,
3. Sodium sulphate.
4. Copper sulphate.

Name the product formed when ethanol reacts with acetic acid. Give an equation.
What is the name given to this type of reaction?

Draw a labeled diagram to show how iron is electroplated with copper.

What is an alloy? How do the properties of an alloy differ from its constituents?

4.5 moles of calcium carbonate are reacted with dilute hydrochloric acid.How many moles of HCl are used in this reaction