The aim of this series “Secrets to Score in Acids, Bases, Salts & Qualitative Analysis” is to help students to the understand the basic concepts surrounding these 2 topics: Acids, Bases & Salts and Qualitative Analysis, and to take a look at the type of questions that are usually associated with it in exams.
This blog-post will be the last post of this typical series and how about checking another typical type of exam-based questions in exams.
Question:
The following excerpts were taken from a student’s chemistry journal.A colourless gas P produced a white precipitate when bubbled into aqueous calcium hydroxide. Gas P was dissolved in water to form a colourless solution Q, which registers a pH of range of 5-6.
Solution Q was then added to a colourless barium solution, known as R. A white precipitate, S, in a colourless solution, T, was observed. Upon filtering, the colourless filtrate, T, was added into a test tube containing aqueous sodium hydroxide and Devarda’s Alloy. The gas evolved turns moist red litmus paper blue.
Identify the following unknowns P, Q, R, S and T. (5 marks)
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