Acids, Bases and Salts — Science STD 10 — Question

An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?

Magnesium ribbon is rubbed before burning because it has a coating of:

A diamond-toothed saw is usually used for cutting:

1. Steel girders.
2. Logs of wood.
3. Marble slabs.
4. Asbestos sheets.

In an experiment to study the properties of ethanoic acid, a student takes about 3 mL of ethanoic acid in a dry test tube. He adds an equal amount of distilled water to it and shakes the test tube well. After some time he is likely to observe that.

Non - metals are:

Sodium hydrogencarbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved?

1. It turns lime water milky.
2. It extinguishes a burning splinter.
3. It dissolves in a solution of sodium hydroxide.
4. It has a pungent odour.

1. 1 and 2
2. 1, 2 and 3
3. 2, 3 and 4
4. 1 and 4

An element which is an essential constituent of all organic compounds belongs to following group of modern periodic table.

1. Group 4.
2. Group 14.
3. Group 15.
4. Group 16.

Soap doesn't work well with woollen garments because :
A. It is basic in nature and woollen garments have acidic dyes.
B. It is acidic in nature and woollen garments have basic dyes.

The pH of the gastric juices released during digestion is:

The metal which is always present in an amalgam is: