Which of the following is a strong acid? MCQ with Answer and Explanation

Explanation:
Portland cement is made by heating a mixture of limestone (CaCO₃) and clay (SiO₂, Al₂O₃, Fe₂O₃) in a kiln. The resulting clinker is ground with gypsum. Soda ash and sand are for glass.

Explanation:
Hydrogen is considered the cleanest fuel because its combustion produces only water (2H₂ + O₂ → 2H₂O) and no greenhouse gases or toxic pollutants. Coal, wood, and diesel produce CO₂, CO, SO₂, and particulate matter, contributing significantly to air pollution and global warming.

Explanation:
Bronze is an alloy primarily of copper and tin, sometimes with other elements. Brass is Cu-Zn. Steel is Fe-C. Duralumin is Al-Cu-Mg-Mn. Bronze is used for statues, coins, and bearings.