How many lone pair (s) of electrons is present in HF?

• A. 0
• B. 1
• C. 2
• D. 3

Which of the following gases is monoatomic?

• A. Argon
• B. Chlorine
• C. Nitrogen
• D. Oxygen

Substances which absorb water from the atmosphere without dissolving in it are sid to be

• A. anhydrous
• B. hygroscopic
• C. insolube
• D. hydrated

The percentage by mass of calcium in Ca(OCI)₂ is [Ca = 40.0; CI = 35.5; O = 16.0]

• A. 28.0%
• B. 31.6%
• C. 43.8%
• D. 44.5%

The valence electrons in a chloride ion are [₁₇CI]

• A. 2p electrons only
• B. 3s and 3p electrons only
• C. 3p and 3d electrons only
• D. 3p electrons only

Which of the following substances is that detergents

• A. are readily available
• B. are in powerdered from
• C. are non-biodegradable
• D. lather readily with water

Atom²³⁴₈₈Q decay by alpha emission to give an atom R. The atomic number and mass number of atom R are respectively

• A. 86 and 230
• B. 87 and 234
• C. 88 and 233
• D. 90 and 238

Element X, with electronic configuration 2, 8, 2 and element Y with electronic configuration 2, 8, 7 are like to combine by

• A. metallic bonding
• B. covalent bonding
• C. electrovalent bonding
• D. dative bonding

The hydrolysis of NH₄Cl salt will give

• A) acidic solution
• B) neutral solution
• C) basic solution
• D) hot solution

The oxidation number of sulphur in Fe₂(SO₄)₃ is

• A. +2.
• B. +3
• C. +4.
• D. +6.