Which one of the following alloys contains a non-metal as one of its constituent ?
- A.Brass
- B.Bronze
- C.Amalgam
- D.Steel
Correct answer
Explanation
The correct answer is D, Steel. Steel is an alloy of iron with a small amount of carbon, and carbon is a non-metal.
Ordinary steel carries roughly 0.05 to 2 per cent carbon. The carbon atoms sit between the iron atoms and stop the layers from sliding easily, which makes steel much harder and stronger than pure iron. Stainless steel adds chromium and nickel to resist rusting, but carbon remains the key non-metal in it. The other three alloys in the list are made only of metals.
A is wrong: brass is copper and zinc, both metals.
B is wrong: bronze is copper and tin, both metals.
C is wrong: an amalgam is mercury mixed with another metal such as silver or tin, so it too has only metals.
Exam tip: steel = iron + carbon; brass = copper + zinc; bronze = copper + tin; amalgam always contains mercury.
Practice Questions
View allSyngamy results in formation of
- A.haploid zygote
- B.diploid zygote
- C.non-motile male gametes
- D.motile male gametes
Show answer
Syngamy is the fusion of a male and a female gamete, and since each gamete is haploid, their union gives a diploid zygote.
Read the full explanation →Human insulin molecule is composed of one α-chain having 21 amino acids and one β-chain having 30 amino acids. How many functional insulin genes occur in adult humans?
- A.One
- B.Two
- C.Three
- D.Four
Show answer
Humans have a single functional insulin gene, INS, on the short arm of chromosome 11, and both chains of insulin come from it.
Read the full explanation →Which one of the following is the value of one nanometer?
- A.10⁻⁷ cm
- B.10⁻⁶ cm
- C.10⁻⁴ cm
- D.10⁻³ cm
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One nanometre is 10⁻⁹ metre, and since one metre is 100 (10²) centimetres, it equals 10⁻⁷ centimetre. The prefix nano means one billionth.
Read the full explanation →Which of the following is the general formula for saturated hydrocarbons?
- A.CₙH₂ₙ₊₂
- B.CₙH₂ₙ₋₂
- C.CₙH₂ₙ₊₁
- D.CₙH₂ₙ₋₁
Show answer
Saturated open-chain hydrocarbons are the alkanes, and every alkane fits the formula CₙH₂ₙ₊₂. In a saturated hydrocarbon every carbon atom is joined to others only by single bonds, so each carbon holds the largest possible number of hydrogen atoms.
Read the full explanation →Which one of the following is not an epidemic disease?
- A.Cholera
- B.Malaria
- C.Smallpox
- D.Elephantiasis
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Elephantiasis, or lymphatic filariasis, is an endemic disease: it stays steadily present in certain regions and develops slowly over years, rather than breaking out suddenly in a large number of people.
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