Which of the following contains ionic, covalent, and coordinate bonds?
A. CO₂
B. NH₄Cl
C. CH₄
D. NaCl
Answer: Option B
Solution (By JKSSB Mock Tests)
Ammonium chloride (NH₄Cl) consists of NH₄⁺ and Cl⁻ ions. Ionic bond between NH₄⁺ and Cl⁻. Within NH₄⁺, N-H are covalent bonds, with one coordinate bond formed by donation of N's lone pair to H⁺. So all three bond types are present. NaCl purely ionic. CO₂ purely covalent. CH₄ purely covalent.
Explanation:
Carbon-14 is a radioactive isotope of carbon with a half-life of about 5,730 years. It is continuously formed in the atmosphere and incorporated into living organisms. When the organism dies, C-14 decays. By measuring the remaining C-14, scientists can determine the age of archaeological and geological samples up to ~50,000 years old.
Explanation:
Bauxite (Al₂O₃·2H₂O) is the principal ore of aluminium. Magnetite (Fe₃O₄) and haematite (Fe₂O₃) are iron ores. Zinc blende is ZnS. Bauxite is refined by Bayer's process to obtain pure alumina, which is then electrolyzed in cryolite.
Explanation:
NaCl + H₂SO₄ (conc.) → NaHSO₄ + HCl↑, at low temperature. At high temperature, NaHSO₄ + NaCl → Na₂SO₄ + HCl. This is the laboratory preparation of HCl gas. Industrial production is by direct combination of H₂ and Cl₂. Nitric acid is an oxidizer and would produce chlorine. Sodium hydroxide gives salt and water (neutralization). Ammonia reacts with acid.
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