Diamond has a high melting point because: MCQ with Answer and Explanation

Diamond has a high melting point because:
A. It is made of carbon
B. It has free electrons
C. It has strong covalent network bonds throughout the crystal
D. It has weak bonds
Answer: Option C
Solution (By JKSSB Mock Tests)
Diamond is a giant covalent structure where each carbon is tetrahedrally bonded to four others via strong covalent bonds. Melting requires breaking numerous strong bonds, needing very high temperature (~3500°C). Graphite also has high melting point. Molecular solids like ice have low melting points. Carbon alone doesn't guarantee high m.p.; it's the structure.

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Practice More chemistry Questions

Question #1
Which of the following species is isoelectronic with CO?
A. NO
B. CO2
C. N2
D. O2

Correct Answer: Option C


Explanation:
Isoelectronic species have the same total number of electrons. Carbon monoxide (CO) has 6 (from C) + 8 (from O) = 14 electrons. Nitrogen molecule (N2) has 7 + 7 = 14 electrons. Therefore, N2 is isoelectronic with CO. O2 has 16, CO2 has 22, and NO has 15 electrons.

This question belongs to: Science chemistry
Question #2
Which of the following reactions is a combination reaction?
A. NaCl + AgNO₃ → AgCl + NaNO₃
B. CaCO₃ → CaO + CO₂
C. Zn + CuSO₄ → ZnSO₄ + Cu
D. 2Mg + O₂ → 2MgO

Correct Answer: Option D


Explanation:
Combination: two or more reactants combine to one product. Mg and O₂ combine to form MgO. A is decomposition; B is displacement; D is double displacement.

This question belongs to: Science chemistry
Question #3
Aqua regia is a mixture of:
A. HF and HCl
B. HNO₃ and H₂SO₄
C. HCl and H₂SO₄
D. HCl and HNO₃ in 3:1 ratio

Correct Answer: Option D


Explanation:
Aqua regia (royal water) is a 3:1 mixture of concentrated HCl and HNO₃. It can dissolve noble metals gold and platinum by forming complex ions. Freshly prepared, it is a fuming yellow liquid. Used in etching and cleaning.

This question belongs to: Science chemistry