Which of the following elements is NOT a p-block element?
A. Bismuth
B. Tin
C. Zinc
D. Gallium
Answer: Option C
Solution (By JKSSB Mock Tests)
The p-block includes elements from groups 13 to 18. Gallium (Group 13), Tin (Group 14), and Bismuth (Group 15) are all p-block elements. Zinc (Group 12) has a completely filled d-subshell (3d10) in its ground state and common oxidation states, placing it in the d-block.
Explanation:
Soap (sodium carboxylate) reacts with Ca²⁺ and Mg²⁺ ions present in hard water to form an insoluble precipitate known as scum. This reduces lathering and wastage of soap. Synthetic detergents do not form scum because their calcium/magnesium salts are soluble.
Explanation:
Urea (NH₂CONH₂) has molar mass 60, with 28 g N, percentage = (28/60)×100 ≈ 46.6%. Rounded to 46%. It is the most concentrated solid nitrogen fertilizer. Ammonium nitrate is 33%, ammonium sulfate 21%.
Explanation:
Ethanol is added to chloroform to inhibit its oxidation to phosgene (COCl₂) – a negative catalyst. Others are positive catalysts that speed up reactions.
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