Which one of the following is an oxidation-reduction reaction?

• NaOH +HCl → NaCl + H₂O

• CaO +H₂O → Ca(OH)₂

• 2Mg + O₂ → 2MgO

• Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl

Which one of the following is not used as fertilizer?

• Ammonium nitrate

• Ammonium sulphide

• Ammonium phosphate

• Ammonium sulphate

Which one of the following is the chemical formula of gypsum?

• CaSO₄.2H₂O

• Ca₂SiO₄

• 2CaSO₄.H₂O

• CaSO₄

Which one of the following statements about the law of conservation of mass is correct?

• A given compound always contains exactly same proportion of elements.

• When gases combine in a reaction, they do so in a simple ratio by volume, provided all gases are at room temperature.

• Matter can neither be created nor destroyed.

• Equal volumes of all gases at same temperature and pressure contain equal number of molecules.

Which one of the following greenhouse gases is in largest concentration in the atmosphere?

• Chlorofluorocarbon

• Nitrous oxide

• Carbon dioxide

• Methane

Which one of the following is not a process of chemical weathering?

• Solution

• Carbonation

• Oxidation

• Exfoliation

The accidental touch of Nettle leaves creates a burning sensation, which is due to inject of:

• Hydrochloric acid

• Methanoic acid

• Citric acid

• Sulphuric acid

Which of the following properties is true for a tooth paste?

• It is acidic

• It is neutral

• It is basic

• It is made up of Calcium phosphate, the material of tooth enamel

Which one of the following gives the highest amount of hydrogen ions (H)?

• Sodium hydroxide solution

• Milk of magnesia

• Lemon juice

• Gastric juice

Brine is an aqueous solution of:

• NaCl

• NaOH

• NaHCO₃

• Na₂CO₃