Chemistry MCQs

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Acids are molecules that are able to donate proton or H+ thus, hydrogen is essential for acids. However, there are exception to this such as Bronsted acids. A Bronsted acid is an acid which can accept an electron pair, but does not have a proton (H+) to donate. Examples of such acids are Aluminum Chloride (AlCl₃), Boron Trifuoride (BF₃).

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Brass is an alloy of Copper and Zinc, in proportions which can be varied to achieve varying mechanical and electrical properties. The proportions of Zinc and Copper can vary to create different types of brass alloys with varying mechanical and electrical properties.

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Polycarbonate(PC) is a tough thermoplastic. It is not only highly transparent but also has good toughness which most of the other thermoplastics do not possess. For this reason, it is widely used for making CDs, Safety Goggles, Mixer jar lids etc.

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Electronegativity is defined as an atom’s ability to attract an electron pair when forming a covalent bond. This property increases as you move left to right across the periodic table due to an increase in the nuclear charge’s attractive forces. It decreases as you move top to bottom, owing to the shielding effect of sub-levels and increased atomic radius, which makes electrons easier to remove. This culminates in Fluorine, being the highest and furthest to the right on the periodic table, hence it is the most electronegative.

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Cassiterite is a mineral that is a significant ore of tin. It is also known as tin oxide. Although rare, its key characteristic is its high specific gravity that makes it easy to separate it from other materials. Tin, which is extracted from Cassiterite, is commonly used in making alloys, punches, and cutting tools.

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Pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice is exceptionally strong and only atoms of nitrogen, boron and hydrogen can be introduced into diamond during the growth at significant concentrations (up to atomic percents). Nitrogen gives yellowish color while the Boron gives bluish color.

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Silica is also known as Silicon dioxide, is the most prevalent form of naturally occurring silicon.

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Aluminium sulphate is also known as Vitriol of clay. It is soluble in water and is mainly used as a flocculating agent in the purification of drinking water

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The attraction between the outer (or valence) electrons and the nucleus increases as the atomic radius decreases in a period. The electronegativity also increases.

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The atomic radius generally decreases across a period. Therefore, Lithium will have the largest atomic radii among the given elements as it is placed before others as we move from left to right in the periodic table.