Acids, Bases and Salts — Science STD 10 — Question

What is meant by ‘rusting’? With labelled diagrams describe an activity to find out the conditions under which iron rusts.

An organic acid X is a liquid, which often freezes during winter time in cold countries, having the molecular formula C₂H₄O₂. On warming it with methanol in the presence of a few drops of concentrated sulphuric acid, a compound Y with a sweet smell is formed.

1. Identify X and Y. Also write their formulae showing the functional group present in them.
2. Write a chemical equation for the reaction involved.

Name three products of the chlor-alkali process. State two uses of each product.

Differentiate between metal and non-metal on the basis of their chemical properties.

Name the functional group of organic compounds that can be hydrogenated. With the help of a suitable example, explain the process of hydrogenation, mentioning the conditions of the reaction and any one change in physical property with the formation of the product. Name any one natural source of organic compounds that are hydrogenated.

What do you mean by a precipitation reaction? Explain giving an example.

Write one chemical equation to represent each of the following types of reactions of organic substances:

1. Esterification.
2. Saponification.
3. Substitution.

Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is

1. Neutral?
2. Strongly alkaline?
3. Strongly acidic?
4. Weakly acidic?
5. Weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction?

You are given a dry cell, a torch bulb with holder, wires and crocodile clips. How would you use them to distinguish between samples of metals and non-metals?