The reaction of zinc with dilute nitric acid does NOT produce hydrogen because:
A. Nitric acid contains no hydrogen
B. Nitric acid is a strong oxidizing agent and oxidizes H₂ to water
C. Zinc is less reactive than hydrogen
D. Zinc does not react with acids
Answer: Option B
Solution (By JKExamLibrary)
Dilute HNO₃ is an oxidizing agent; it oxidizes the hydrogen produced to water and itself gets reduced to nitrogen oxides (NO, N₂O, etc.). Very dilute HNO₃ with Mg/Mn can produce H₂. Metals above hydrogen normally displace H₂ from non-oxidizing acids like HCl.
Explanation:
Oxidation is defined as the loss of electrons (or an increase in oxidation state). A reducing agent is a substance that donates electrons to another species, thereby causing the other species to be reduced. In doing so, the reducing agent itself gets oxidized. Thus, statement 1 is correct, but 2 is incorrect.
Explanation:
Elements in the same group (vertical column) have the same number of valence electrons, resulting in similar chemical properties. For example, all Group 1 elements have 1 valence electron (ns¹). The number of shells increases down the group. Atomic mass varies. This similarity was the basis for Mendeleev's grouping. Modern table uses atomic number for ordering.
Explanation:
Hydrogenation adds hydrogen to unsaturated vegetable oils in the presence of nickel catalyst at about 150°C, converting liquid oils (C=C bonds) to solid fats (vanaspati ghee) with higher melting points. Saponification makes soap. Esterification forms esters. Fermentation produces alcohol. Partial hydrogenation can produce trans fats, which are harmful. Complete hydrogenation yields saturated fats.
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