Differentiate between acids, bases and alkalis.

• A. Acids donate H+, bases accept H+, and alkalis are bases that dissolve in water.
• B. Acids turn blue litmus paper red; bases turn green; alkalis are salts.
• C. Acids are slippery; bases are sour; alkalis are inert gases.
• D. Acids are produced by plants; bases are produced by animals; alkalis are minerals.

Answer: (A)

Acids donate H+ ions in solution, bases accept H+ ions, and alkalis are bases that dissolve in water to form alkaline solutions. This links proton transfer to the everyday idea of alkalinity: acids release H+ in water, bases grab H+ (often using OH− to form water), and alkalis are the soluble bases that make the solution alkaline.

For example, hydrochloric acid splits to give H+ in water; ammonia acts as a base by accepting a proton to become NH4+; and sodium hydroxide dissolves to give OH− in water, which raises the pH and creates an alkaline solution. That combination of proton donation, proton acceptance, and solubility in water defining alkalis makes this description the most accurate.

Other statements mix up properties or make incorrect claims—bases aren’t described as turning green on litmus, alkalis aren’t simply salts, and acids aren’t defined by slipperiness while bases aren’t defined by sourness.