Question

Read the given passage and answer the following questions:

A student found a piece of substance in a laboratory. He was quite interested in learning more about that material and tried to classify it as a metal and non-metal. With that knowledge he analysed the properties of that unknown material. Because the substance is soft, he assumed it was non-metal, but it had a shining appearance as generally speaking non-metals are not shiny. He assumed this material to be iodine. On hammering, he observed that he was able to get a thin sheet of that material. He intended to undertake an experiment to analyse more about that material and so he made a small electric circuit using a battery, switch, and electric wires and the unknown element. The outcome surprised him as the bulb in this setup glowed.

A) Why does he suspected that the unknown material could
be iodine?
B) Was his suspicion correct?
C) What could be the unknown element?
[3 Marks]

Answer 1

A) He suspected that the unknown material could be
iodine as iodine is a lustrous non-metal. [1 Mark]
B) No, his suspicion was incorrect as iodine is
non-malleable and also does not conduct
electricity as seen in other two observations.
[1 Mark]
C) The unknown material can either be sodium or
potassium as both of them are soft metals.
[1 Mark]