Rita added dilute hydrochloric acid to four metals. She recorded her observations in the table given below. While noting her observations she made some errors. Metals Observations 1 copper a gas was given off 2 iron a gas was given off 3 magnesium no gas was given off 4 zinc a gas was given off Which observation(s) made by Rita is/are correct? (a) 1 only (b) 3 only (c) Both 1 and 4 (d) Both 2 and 4

Give one significant observation when: (a) Barium chloride solution is added to zinc sulphate solution. (b) Lead nitrate is heated strongly. (c) Chlorine gas is passed through moist starch iodide paper.

You are provided with some compounds in the box. PbO CH4 PbO2 CO2 HCl NCl3 SO2 Choose the most appropriate compound which fits the descriptions (a) to (c) given below: (a) A colourless gas which turns acidified K2Cr2O7 from orange to green. (b) A yellow explosive oily liquid formed when excess chlorine gas reacts with ammonia gas. (c) A yellow metallic oxide formed on thermal decomposition of PbCO3.

Give one relevant observation for the following: (a) Sodium hydroxide is added dropwise to Calcium nitrate solution. (b) Dilute Hydrochloric acid is added to Iron (II) sulphide. (c) An amphoteric metal is added to hot concentrated alkali.

Assertion (A): Dilute Sulphuric acid is a stronger electrolyte than concentrated Sulphuric acid. Reason (R): Dilute Sulphuric acid has a higher concentration of mobile ions. (a) (A) is true but (R) is false. (b) (A) is false but (R) is true. (c) Both (A) and (R) are true and (R) is the correct explanation of (A). (d) Both (A) and (R) are true, but (R) is not the correct explanation of (A).

An atom of X forms an ion according to the equation X ⟶ X+2. The atomic number of the atom X is: (a) 16 (b) 10 (c) 12 (d) 14

Assertion (A): In the electrolysis of acidified water, the volume of hydrogen liberated is twice the volume of oxygen formed. Reason (R): Water has hydrogen and oxygen in the ratio of 1:2 by volume. (a) (A) is true but (R) is false. (b) (A) is false but (R) is true. (c) Both (A) and (R) are true and (R) is the correct explanation of (A). (d) Both (A) and (R) are true, but (R) is not the correct explanation of (A).

The electronic configuration of an element is 2,8,2. The hydroxide of this element can produce ............... hydroxyl ions per molecule. (a) 3 (b) 2 (c) 1 (d) 0

In the electrolysis of molten aluminium oxide for extraction of aluminium, the following reactions take place: 1. 2. 3. 4. The reaction that takes place at the negative electrode is: (a) 1 (b) 2 (c) 3 (d) 4

A hydrocarbon X undergoes the reaction under suitable conditions as shown below: Which compound(s) is/are unsaturated? (a) X only (b) Y only (c) X and Z (d) Y and Z

The ore that can be concentrated by using magnetic separation: (a) Corundum (b) Haematite (c) Calamine (d) Bauxite

What volume of carbon dioxide is produced at STP when 5 litres of propane is burnt completely according to the equation given below? (a) 10 litres (b) 15 litres (c) 20 litres (d) 25 litres