Which of the following is NOT a redox reaction?
Correct answer: C. NaOH + HCl gives NaCl + H2O
- A. Zn + 2HCl gives ZnCl2 + H2
- B. 2H2 + O2 gives 2H2O
- C. NaOH + HCl gives NaCl + H2O
- D. 2Mg + O2 gives 2MgO
Explanation
In neutralisation no element changes its oxidation number, since hydrogen stays at plus 1, oxygen at minus 2 and both sodium and chlorine keep their values throughout, so only ions are rearranged. In the other three reactions a metal or hydrogen changes from zero to a positive state while another element is reduced. Checking oxidation numbers on both sides is the reliable test.
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About Redox Reactions
Redox reactions involve oxidation and reduction occurring together, with electrons transferred between species or oxidation numbers changing. The topic covers assigning oxidation states, identifying oxidizing and reducing agents, balancing redox equations by oxidation number or half-reaction methods, and connecting chemical changes with galvanic and electrolytic cells.
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