An element belongs to third period and sixteenth group. It will have …………… electrons in its valence shell.

1. 2
2. 5
3. 6
4. 3

The setup shown below is that of the fountain experiment with hydrogen chloride gas in the flask.

The fountain starts when a few drops of water from the dropper are introduced into the flask. Instead of the drops of water, Pooja started the fountain by introducing a few drops of Sodium hydroxide into the flask.

(a) Explain why the litmus solution gets sucked up when Sodium hydroxide is used.

(b) What will be the colour of the fountain when Sodium hydroxide is used? Justify your answer.

(c) If instead of HCl gas, ammonia gas is filled in the flask and water is introduced from the dropper, will there be a different observation? Justify your answer.

Complete the following by choosing the correct answers from the bracket:

(a) If an element has one electron in the outermost shell then it is likely to have the ……………. [smallest/ largest] atomic size amongst all the elements in the same period.

(b) ……………. [sulphuric acid/ hydrochloric acid] does not form an acid salt.

(c) A ……………. [reddish brown/ dirty green] coloured precipitate is formed when ammonium hydroxide is added to a solution of ferric chloride.

(d) Alkanes undergo ……………. [addition/ substitution] reactions.

(e) An ……………. [alkaline/acidic] solution will turn methyl orange solution pink.

Identify the following:

(a) A bond formed between two atoms by sharing of a pair of electrons, with both electrons being provided by the same atom.

(b) A salt formed by the complete neutralization of an acid by a base.

(c) A reaction in which the hydrogen of an alkane is replaced by a halogen.

(d) The energy required to remove an electron from a neutral gaseous atom.

(e) A homogenous mixture of two or more metals or a metal and a non-metal in a definite proportion in their molten state.