SSC
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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TRUE
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FALSE
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Either A or B
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None of the above
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Detailed explanation-1: -A pure substance always has a definite and constant composition. A mixture is a physical combination of two or more pure substances in which each substance retains its own chemical identity. A pure substance is a single substance on its own. Elements and compounds are pure substances, but mixtures are not.
Detailed explanation-2: -The law is true for the compounds obtained from one isotope, like 12C/14C. Hence, no, the law of constant composition is true for all types of compounds. Note: Elements containing a mixture of stable isotopes also form non-stoichiometric compounds.
Detailed explanation-3: -A mixture does not have a fixed melting point, boiling point etc. On the other hand, compounds have a a fixed melting point, boiling point.