Free Chemistry in Daily Life MCQs with Answers

221. Calcium sulphate is known as__________?

• A. Epsom salt
• B. Gypsum salt
• C. Blue vitriol
• D. Potash alum

Explanation: Calcium sulphate commonly occurs as gypsum, especially as hydrated calcium sulphate. Epsom salt is magnesium sulphate, while blue vitriol is copper sulphate.

222. Epsom salt is chemically known as_________?

• A. Copper Sulfate
• B. Magnesium Sulfate
• C. Ferrous Sulfate
• D. None of these

Explanation: Epsom salt is magnesium sulphate, usually written as MgSO₄·7H₂O because it commonly occurs in hydrated form. Copper sulphate is blue vitriol, not Epsom salt.

223. The element used in lead pencils is__________?

• A. Zinc
• B. Lead
• C. Carbon
• D. Tin

Explanation: The writing core of a lead pencil is graphite, a form of carbon, not metallic lead. Its layered carbon structure leaves marks on paper.

224. The alcohol used in the preparation of dynamite is________?

• A. ethyl alcohol
• B. glycerol
• C. glycol
• D. methyl alcohol

Explanation: Dynamite is prepared using nitroglycerin, which is made by nitrating glycerol or glycerine. Ethyl and methyl alcohols are not the alcohol used for this explosive.

225. First Atomic theory was proposed by?

• A. John Dalton
• B. E.Rutherford
• C. De Broglie
• D. D.I.Mendeleef

Explanation: John Dalton proposed the first modern atomic theory in the early nineteenth century, explaining matter as combinations of atoms. Rutherford and later scientists refined the model rather than proposing the original theory.

226. Ruby is an oxide of__________?

• A. silver
• B. gold
• C. platinum
• D. aluminium oxide

Explanation: Ruby is mainly crystalline aluminium oxide, Al₂O₃, with traces of chromium giving it its red colour. Thus it is an aluminium oxide rather than an oxide of silver, gold, or platinum.

227. Bauxite is an ore of_________?

• A. copper
• B. zinc
• C. aluminium
• D. iron

Explanation: Bauxite is the principal ore of aluminium and contains hydrated aluminium oxides. It is not the chief ore of copper, zinc, or iron.

228. Who created periodic table?

• A. Faraday
• B. Lavoisier
• C. Arrhenius
• D. Mendeleev

Explanation: Dmitri Mendeleev created the first widely useful periodic table in 1869 and left gaps for elements not yet discovered. The other scientists listed made important contributions to chemistry but did not create this table.

229. Which of the following is the most toxic gas?

• A. Carbon dioxide
• B. Carbon monoxide
• C. Nitrogen
• D. Hydrogen

Explanation: Carbon monoxide is highly toxic because it binds haemoglobin strongly and prevents blood from carrying oxygen. Nitrogen and hydrogen are not poisonous at ordinary concentrations, while carbon dioxide is mainly dangerous at high concentrations.

230. Which one of the following gases is readily soluble in water at room temperature?

• A. Chlorine
• B. Nitrogen
• C. Ammonia
• D. Carbon dioxide

Explanation: Ammonia dissolves very readily in water and forms an alkaline solution called ammonium hydroxide in traditional descriptions. Nitrogen is only slightly soluble, and carbon dioxide is much less soluble than ammonia.