Chemistry Past Questions and Answers

Which of the five atoms can be described by the following properties: Relative atomic mass is greater than 30 but less than 40, it has odd atomic number and forms a unipositive ion in solution?

A solid X when heated gives off a brown gas. If X is soluble in excess sodium hydroxide solution but insoluble in excess ammonium hydroxide solution, then X is

Consider the solubility curves of three salts X, Y and Z given in the diagram. If each solution of the salt contains 200 g, and is heated to 100<sup style='font-size: smaller;'>o</sup>C, which solution or solutions will deposit 100 g of the solute when suddenly cooled to 0<sup style='font-size: smaller;'>o</sup>C?

An experiment test of the Law of conservation of Mass is illustrated in the diagram. In practice, the flask is weighed before and after reaction between solutions X and Y. Which of the following pairs of solutions will be unsuitable for the experiments

Five compounds R,T,W,X and Y form the following compounds: a basic hydride R.H, an acidic hydride YH, atmospheric oxide W<sub style='font-size: smaller;'>2</sub>O<sub style='font-size: smaller;'>3</sub>, XO<sub style='font-size: smaller;'>2</sub>. which of the elements is an alkali