Tag: science & technology

This question asks which author-work pairing is INCORRECT. Vishwas Patil is famous for 'Zandi' (about the 1857 revolt), not 'Zombi'. The other three pairings are all correct Marathi literary works by their respective authors.

Milk contains lactic acid, which is produced when bacteria ferment lactose (milk sugar). Fresh milk contains very little lactic acid, but it increases as milk sours or ferments into products like yogurt. Oxalic acid is found in spinach, citric acid in citrus fruits, and boric acid is not naturally found in food.

Chlorine gas (Cl2) is greenish-yellow in color, which gives it its name from the Greek 'chloros' meaning greenish-yellow. Hydrogen is colorless, Neon is reddish-orange in discharge tubes but colorless as a gas, and Krypton is colorless.

In the tertiary structure of proteins (including keratin in hair), disulfide bonds form between the sulfur atoms in cysteine amino acid R groups. These covalent bonds provide structural stability and are responsible for hair's strength. Carbon-carbon bonds don't specifically link R groups, hydroxide is not a bond type, and dihydride is not a relevant term.

Ammonia (NH3) is a basic gas widely used in fertilizer production, including urea manufacture. The Haber process combines nitrogen and hydrogen to produce ammonia. Hydrogen is neutral, nitrogen is inert, and chlorine is acidic - none are basic or used in urea production.

Carbonic acid (H2CO3) is responsible for carbonation in soft drinks. When CO2 dissolves in water under pressure, it forms carbonic acid, which creates the 'fizz' and tingling sensation. Citric acid adds flavor but not fizz, acetic acid is in vinegar, and oxalic acid is toxic.

Pencil 'lead' is actually graphite, a form of carbon. The misconception comes from graphite historically being called 'black lead.' Plastic is used in pencil casings, carbon black is a pigment, and lead is toxic and never used in pencils.

Sulfuric acid (H2SO4) is historically known as 'Oil of Vitriol.' The term 'vitriol' refers to sulfate salts, and sulfuric acid was the most important. Hydrochloric acid is 'muriatic acid,' and neither hydroiodic nor nitric acid have this common name.

Vinegar is very dilute acetic acid (typically 4-8% acetic acid in water). Citric acid is in citrus fruits, carbonic acid is in carbonated water, and phosphoric acid is in some dark sodas but not vinegar.

Gold is often found in the pure (native) state because it is unreactive and doesn't easily oxidize or form compounds. Magnesium, Silver, and Iron are reactive and are typically found as ores or compounds that need refining.