The main chemical constituent of clay is ?
Answer: C
Clay is chiefly aluminium silicate.
Kaolinite, \(\mathrm{Al_2Si_2O_5(OH)_4}\), forms by the weathering of feldspar. Its layered sheet structure lets the plates slide over one another when wet, which is what makes clay plastic and mouldable.
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Air contains maximum amount of
Answer: B
Air contains most nitrogen, about 78 per cent by volume.
Oxygen makes up 21 per cent, argon 0.93 per cent and carbon dioxide about 0.04 per cent. Free hydrogen is present only in traces, being light enough to escape into space.
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An alloy is
Answer: D
An alloy is a mixture.
It is a homogeneous mixture of two or more metals, or of a metal with a non-metal, in no fixed proportion - brass may be 60–90 per cent copper. Because the composition can vary, an alloy is not a compound.
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Which is the Lightest of all the metals?
Answer: B
Lithium is the lightest metal, with a density of \(0.53\ \mathrm{g\,cm^{-3}}\).
It is only about half as dense as water, so it floats on it - as do sodium (0.97) and potassium (0.86). Hydrogen is lighter still but is a non-metal under ordinary conditions.
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The enzyme in whose presence glucose and fructose are converted into alcohol is
Answer: D
Zymase converts glucose and fructose into alcohol.
\[\mathrm{C_6H_{12}O_6 \xrightarrow{zymase} 2\,C_2H_5OH + 2\,CO_2}\] It is a complex of enzymes secreted by yeast. Invertase acts earlier in the sequence, splitting sucrose into the two hexoses that zymase then ferments.
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Which of the following processes is used to remove reducible oxides from the metal?
Answer: C
Poling removes reducible oxides from a metal.
Molten metal is stirred with green wooden poles; the wood gives off hydrocarbon gases that reduce the oxide back to the metal. It is used to refine copper containing cuprous oxide, and tin. Liquation separates by melting point, cupellation removes lead from silver, and electrorefining works by electrolysis.
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Which among the following is not important for individual’s health?
Answer: D
Living in a large and well furnished house is not important for health.
Health depends on clean surroundings, adequate food and income, and social equality and harmony, which determine whether a person can actually obtain those things. The size or furnishing of a house adds comfort but not health.
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What is the element present in urea
Answer: D
Urea contains carbon, oxygen, nitrogen and hydrogen.
Its formula is \(\mathrm{NH_2CONH_2}\), or \(\mathrm{CO(NH_2)_2}\). Wöhler's synthesis of urea from ammonium cyanate in 1828 was the first preparation of an organic compound from an inorganic one, and ended the vital-force theory.
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Which of the properties of the element is a whole number
Answer: B
The atomic number is always a whole number.
It counts the protons in the nucleus, and one cannot have a fraction of a proton. Atomic mass is an average weighted over the natural isotopes and so is usually fractional, as with chlorine's 35.5, while radius and volume are measured quantities.
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The number of atoms present in 21.6 gram of silver (atomic weight = 108) are same as the molecules in
Answer: B
The answer is 0.2 mole of \(\mathrm{KMnO_4}\).
\[n(\mathrm{Ag})=\frac{21.6}{108}=0.2\ \text{mol}\]
so the sample contains \(0.2\,N_A\) atoms. The option that contains the same number of particles is the one holding 0.2 mole of molecules. For comparison, 1.8 g of \(\mathrm{H_2O}\) and 4.6 g of \(\mathrm{C_2H_5OH}\) are each 0.1 mole.
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