Chemical Reactions and Equations — Science STD 10 — Question

The property which is not shown by acids is:

1. They have sour taste.
2. They feel soapy.
3. They turn litmus red.
4. Their pH is less than seven.

Which of the following metals can be obtained from haematite ore?

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.

A student takes about 6 ml of distilled water in each of the four test tubes P, Q, R and S, then dissolves an equal amount of four different salts namely sodium chloride in ‘P', potassium chloride in ‘Q', calcium chloride in ‘R' Cand magnesium chloride in ‘S'. He then adds 10 drops of soap solution to each test tube and shakes its contents. The test tubes in which scum (insoluble substance) is formed with soap are:

Calamine ore can be used to extract one of the following metals. This metal is:

1. Copper.
2. Mercury.
3. Aluminium.
4. Zinc.

An alloy is:

Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper. What would be the colour obtained? (You may use colour guide given in Figure:

1. Red.
2. Yellow.
3. Yellowish green.
4. Blue.

A student adds a few drops of ethanol acid to test tubes X, Y and Z containing aqueous solutions of sodium chloride, sodium hydroxide and sodium carbonate respectively. If he now brings a burning splinter near the mouth of the test tubes immediately after adding the ethanol acid in each one of them, in which of the test tube or test tubes the flame gets extinguished?

A solution reacts with zinc granules to give a gas which burns with a 'pop' sound. The solution contains:

1. Mg(OH)₂
2. Na₂CO₃
3. NaCl
4. HCl