
A solution X was tested by a student in various ways with different materials. The following results were obtained.
(1) Solution X gave no colour change with red litmus, but blue litmus turned red.
(2) Solution X turned universal indicator solution from green to orange.
(3) Solution X produced a slow 'fizzing' reaction with a marble chip. The gas formed gave a milky white precipitate when bubbled into limewater.
(4) Solution X produced a moderate 'fizzing' reaction with a strip of magnesium metal. A test tube of the gas formed gave a squeaky pop with a lit splint.
(5) Solution X produced a moderate 'fizzing' reaction with a pinch of 'bicarbonate of soda' powder. The gas formed gave a milky white precipitate when bubbled into limewater.
What could the student
deduce about solution X from the results? [7f-59]