The question asks us to identify a compound 'X' that melts at low temperature and is a bad conductor of electricity in both the liquid and solid states. Let's analyze the given options to determine which one fits this description.
Carbon tetrachloride (CCl4):
- Carbon tetrachloride is an organic compound that has a relatively low melting point of about -23°C.
- It is non-polar and exists as discrete molecules, which do not conduct electricity in either the solid or liquid state. Conclusion: Carbon tetrachloride matches both the criteria: it melts at a low temperature and is a bad conductor of electricity.
Silicon carbide (SiC):
- Silicon carbide is a covalent compound with a very high melting point (over 2,700°C).
- It is known to be a very good conductor of electricity in its solid form. Conclusion: Silicon carbide does not fit the requirements as it has a high melting point and conducts electricity well.
Mercury (Hg):
- Mercury is a metal with a melting point of -38.83°C, which would classify it as having a low melting point.
- However, mercury is an excellent conductor of electricity in the liquid state. Conclusion: Mercury cannot be 'X' because it is a good conductor of electricity.
Zinc sulphide (ZnS):
- Zinc sulphide has a higher melting point (around 1,185°C) compared to carbon tetrachloride.
- It is an insulator, meaning it does not conduct electricity in the solid state, but the melting point disqualifies it. Conclusion: Zinc sulphide fails to meet the low melting point criteria.
From the analysis above, the only compound that satisfies both criteria of having a low melting point and being a poor conductor of electricity in both states is Carbon Tetrachloride (CCl4).
