When concentrated H₂SO₄ splits on the surface, it should be immediately cleaned:

• with a piece of cloth.

• by adding cold water.

• by adding solid Na₂CO₃

• by adding solid BaCl₂.

A bee-sting leaves an acid that causes pain and irritation. The injected acid is

• acetic acid

• sulphuric acid

• citric acid

• methanoic acid

Iron nails are dipped into blue copper sulphate solution. After some time iron nails are:

• dissolved and blue color is discharged

• dissolved but blue color is not discharged

• not dissolved but the blue color is not discharged

• not dissolved but the blue color is discharged

A student by the chance of mixed acetone with alcohol. This mixture of acetone and alcohol can be separated by

• filtration.

• separating funnel.

• fractional crystallization.

• fractional distillation.

Silverware turns black after a period of time due to the formation of:

• nitrate coating on silver.

• sulphide coating on silver.

• chloride coating one silver.

• oxide coating on silver

Which of the statements given below is/are correct Permanent hardness of water is due to the presence of soluble:

1. chloride of calcium.
2. bicarbonate of calcium
3. sulphate of magnesium.
4. bicarbonate of magnesium

Select the correct answer using the code given below:

• 1 only

• 1 and 3 only

• 2 and 4

• 1, 2 and 3

Bronze is often used to make statues and medals whereas brass is used in making utensils, scientific apparatus and cartridges. Both brass and bronze are copper-containing alloys, yet they differ in their chemical composition for additionally containing:

• Zinc in brass and tin in bronze

• Chromium in brass and nickel in bronze.

• Nickel in brass and tin in bronze.

• Iron in brass and nickel in bronze

Which of the statements about glass are correct?

1. Glass is a super-cooled liquid having infinite viscosity
2. Violet coloured glass is obtained by adding MnO_2\
3. Glass is a man-made silicate
4. Glass is a crystalline substance

Select the correct answer using the code given below:

• 1, 2 and 4

• 2, 3 and 4

• 1, 2 and 3

• 1 and 3 only

Which among the following are the properties of good paint?

1. The paint should be opaque and have high covering power
2. The solid particles in the paint should reflect much of the destructive light to ensure the long life of the paint
3. Combination of pigments, e.g., white lead and TiO₂ give better result
4. The addition of plasticizer destroy the elasticity of the film and leads to cracking

Select the correct answer using the code given below:

• 1, 2 and 4

• 1, 2 and 3

• 2 and 3 only

• 1 and 3 only

By which one among the following mechanism, soap removes dirt (soil) from cloth?

• Soap dissolves the soil as such

• Soap reacts with soil and converts them into soluble silicates

• Soap takes away the oily part of the soil and thus separates the soil from the cloth

• The soap molecules bind with the soil, lift the soil and keep it suspended which can then be rinsed away