Class X A student placed an iron nail in copper sulphate solution. He observed the reddish brown coating on the iron nail which is soft and dull hard and flading smooth and shining rough and granular An element reacts with oxygen to give a compound with a high melting point. The compound is soluble in water. The element is likely to be calcium carbon iron silicon Silver articles becomes black on prolonged exposure to air. This is due to the formation of Ag2O Ag2S AgCN Ag2O and Ag2S Rusting of iron takes place in ordinary water distilled water both ordinary and distilled water none of the above A student placed an iron nail in copper sulphate solution. He observed the reddish brown coating on the iron nail which is soft and dull hard and flading smooth and shining rough and granular Do you really want to submit this quiz? Cancel Submit Quiz