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This SSC CGL Chemistry question asks: “The basicity of H3PO3 (phosphorous acid) is” The correct answer is 2. H3PO3 has 2 P-OH groups and 1 P-H bond. Only P-OH groups dissociate so basicity is 2 (dibasic acid). Acid basicity refers to the number of ionisable protons, not simply the number of hydrogen atoms written in a formula.
issociate so basicity is 2 (dibasic acid). H3PO3 has 2 P-OH groups and 1 P-H bond. Only P-OH groups dissociate so basicity is 2 (dibasic acid).
FAQ
Common questions and clear answers for this topic.
Chemistry usually contributes a handful of questions within the General Awareness section, generally covering basic concepts rather than calculation-heavy problems.
Atomic structure, periodic table trends, acids-bases-salts, metals and non-metals, and carbon compounds are the areas that appear most consistently across past papers.
NCERT textbooks from classes 9 and 10 cover most of the conceptual base needed, though supplementing with general knowledge about everyday chemical compounds helps too.
Linking reactions to real-world examples, like rusting or antacids, makes them easier to recall than memorizing formulas in isolation.
Yes, a large part of the syllabus mirrors class 9 and 10 science, making school-level revision a practical starting point.
