Multiple choice general knowledge science & technology When an iron nail gets rusted, iron oxide is formed without any change in the weight of the nail with decrease in the weight of the nail with increase in the weight of the nail without any change in colour or weight of the nail Reveal answer Fill a bubble to check yourself C Correct answer Explanation When iron rusts, it combines with oxygen to form iron oxide (Fe2O3·xH2O), which adds oxygen atoms to the original iron. Since oxygen has mass, the rusted nail weighs more than the pure iron nail.