Galvanization is coating iron with: MCQ with Answer and Explanation

Explanation:
Reacting with metals (e.g., Zn + 2HCl → ZnCl₂ + H₂) to produce hydrogen gas is a chemical property because new substances are formed. Sour taste is physical sensation, color change of litmus is an indicator of chemical reaction but is not itself a chemical property; reactivity is. Conductivity is physical. Chemical properties describe a substance's ability to undergo chemical change.

Explanation:
Magnesium reacts with hot water or steam to form MgO/Mg(OH)₂ and H₂, but very slowly with cold water (thin layer of insoluble hydroxide inhibits reaction). Sodium, potassium, and calcium react vigorously with cold water. Aluminium, zinc, iron react with steam but not cold water. Reactivity with water follows the series: K, Na, Ca (cold water); Mg, Al, Zn, Fe (steam).

Explanation:
Petroleum originates from microscopic marine organisms (plankton) that sank to the seabed and were transformed by heat/pressure over millions of years. Coal is from land plants.