Which of the following statement is or are incorrect? Mark as favorite Copy Link All metals except mercury exist as solids at room temperature. Most non-metals produce acidic oxides when dissolve in water. Alkali metals (lithium, sodium, potassium) are so soft that they can be cut with a knife. Platinum, is an allotrope of carbon, is the hardest natural substance known and has a very high melting and boiling point. Check Answer