Which of the following is a chemical property of acids? MCQ with Answer and Explanation

Explanation:
Metalloids (B, Si, Ge, As, Sb, Te) are located along the staircase line on the right side of the p-block, dividing metals from non-metals. They exhibit intermediate properties: semiconductors, brittle, can form alloys. They are in groups 13-17. The s-block contains reactive metals. Group 18 contains noble gases. f-block contains lanthanides and actinides.

Explanation:
Permanent hardness (due to CaSO₄ etc.) can be removed by adding Na₂CO₃, which precipitates CaCO₃. Boiling only removes temporary hardness. Ion exchange and calgon also work.

Explanation:
CO removes oxygen from Fe₂O₃ – it's a redox reaction. Also, CO displaces Fe, making it a displacement. So both redox and displacement.