Which of the following statements are false?
- 18-carot gold consists of Au 58%, Cu 12–28% and Ag 4–30%.
- Sterling-S alloy contains Ag 82.5% and Cu 17.5%.
- Naval brass is composed of Cu 60%, Zn 39.25% and Sn 0.75%.
- Dow’s metal consists of 93.8% Mg, 6% Al and 0.2% Mn.
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1 and 2
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2 and 3
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3 and 4
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1, 2 and 3
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2, 3 and 4
A
Correct answer
Explanation
- 18-carot gold contains Au 75%, Ag 10–20% and Cu 5–15%.
Gold 14-carot consists of Au 58%, Cu 12–28% and Ag 4–30%.
- Sterling-S (sterling silver) alloy is composed of Ag 92.5% and Cu 7.5%.
- The composition of Naval brass is Cu 60%, Zn 39.25% and Sn 0.75%.4.
Dow’s metal is composed of 93.8% Mg, 6% Al and 0.2% Mn.
Hence, both 1 and 2 are false.