Arrange the following substances in chronological order of their first synthesis in lab : 1. Black gold 2. Fullerene 3. Graphene 4. Kevlar Select correct answer from the codes given below : Codes :
- (a)1 2 3 4
- (b)4 2 3 1
- (c)2 4 3 1
- (d)4 1 2 3
Correct — B, the order 4-2-3-1: Kevlar, then Fullerene, then Graphene, then Black gold. Kevlar (1965) is the oldest — the para-aramid fibre invented by Stephanie Kwolek at DuPont, five times stronger than steel by weight and the material of body armour, helmets and high-performance ropes. Fullerene came next: buckminsterfullerene, C60, the closed carbon cage shaped like a football, was discovered in 1985 by Harold Kroto, Robert Curl and Richard Smalley, who shared the 1996 Nobel Prize in Chemistry for it. Graphene — a single one-atom-thick sheet of carbon — was isolated in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester using the celebrated adhesive-tape method, and won the 2010 Nobel Prize in Physics. Black gold is the newest by a wide margin and the reason this question appeared in a December 2019 paper at all: it was reported in July 2019 by a team at the Tata Institute of Fundamental Research, Mumbai, led by Prof. Vivek Polshettiwar, and published in the Royal Society of Chemistry journal Chemical Science. So 1965 → 1985 → 2004 → 2019, that is 4, 2, 3, 1.
- (a)1 2 3 4 — This is simply the list in its printed order, and it inverts the two endpoints: it puts black gold (2019, the most recent of the four) first and Kevlar (1965, the oldest) last. Sequence questions frequently offer the untouched list as a decoy for candidates who run out of time.
- (c)2 4 3 1 — Gets graphene and black gold right at positions three and four, but swaps the first pair — it places fullerene (1985) before Kevlar (1965). Fixing Kevlar as the oldest of the four is the single check that kills this option.
- (d)4 1 2 3 — Starts correctly with Kevlar, then collapses: it puts black gold (2019) second, ahead of both fullerene (1985) and graphene (2004). Candidates fall for it when they treat 'black gold' as the old metaphor for petroleum or coal rather than as the 2019 nanomaterial.
Three of the four substances in this list are carbon materials and mark the milestones of materials science over half a century: an aramid polymer (Kevlar), a molecular carbon cage (fullerene) and a two-dimensional carbon sheet (graphene). The fourth, 'black gold', is not carbon at all — it is a gold nanomaterial, made of gold nanoparticles arranged as dendritic plasmonic colloidosomes, whose spacing was tuned so that the material absorbs almost the entire visible and near-infrared spectrum and therefore looks black instead of yellow. Its reported applications are solar-driven conversion of carbon dioxide to methane and solar seawater desalination.
Chronology questions are solved by anchoring the extremes, not by recalling all four dates. Here the two anchors are easy: Kevlar belongs to the 1960s and is plainly the oldest; black gold was a mid-2019 Indian result, four months before this exam, and is plainly the newest. Any option that does not begin with 4 and end with 1 can be struck out immediately — and that alone leaves only option (b). The name is the trap: 'black gold' is a long-standing metaphor for petroleum and sometimes for coal, so a candidate who has not seen the July 2019 TIFR news reads it as something ancient and places it first.
- Kevlar, 1965 — para-aramid fibre invented by Stephanie Kwolek at DuPont; used in bulletproof vests, helmets, tyres and ropes.
- Fullerene (C60, buckminsterfullerene), 1985 — discovered by Harold Kroto, Robert Curl and Richard Smalley, who received the 1996 Nobel Prize in Chemistry.
- Graphene, 2004 — a single-atom-thick sheet of carbon isolated by Andre Geim and Konstantin Novoselov at Manchester; 2010 Nobel Prize in Physics.
- Black gold, July 2019 — developed at the Tata Institute of Fundamental Research, Mumbai, by a team led by Prof. Vivek Polshettiwar and reported in Chemical Science; absorbs nearly the whole visible and near-infrared spectrum, and was demonstrated for solar-powered carbon dioxide to methane conversion and seawater desalination.
- Do not read 'black gold' here as petroleum or coal — in this question it is the 2019 gold nanomaterial, which is also why the item is a gold, not a carbon, substance in a list otherwise made of carbon materials.
- 1965 — Kevlar (item 4): para-aramid fibre, Stephanie Kwolek at DuPont; body armour, helmets, ropes
- 1985 — Fullerene C60 (item 2): the carbon 'buckyball', Kroto, Curl and Smalley; Nobel Chemistry 1996
- 2004 — Graphene (item 3): one-atom-thick carbon sheet isolated by Geim and Novoselov at Manchester; Nobel Physics 2010
- July 2019 — Black gold (item 1): dendritic plasmonic gold nanomaterial from TIFR Mumbai (Prof. Vivek Polshettiwar), reported in Chemical Science
Answer (b): 4, 2, 3, 1. Anchoring Kevlar as the oldest and black gold — the July 2019 Indian result — as the newest eliminates the other three codes at once.
- Reading 'black gold' as petroleum or coal and therefore placing it first — in this question it is the 2019 TIFR nanomaterial.
- Assuming all four items are carbon materials; black gold is gold-based, which is exactly why it stands out in the list.
- Confusing the DISCOVERY of an allotrope with the isolation of a single layer — graphite has been known for centuries, but single-layer graphene was isolated only in 2004.
Both UPSC and UPPSC pair a current Indian research result with older, well-known materials and ask you to sequence or identify them. UPSC's own graphene (2012) and carbon nanotube (2020) questions show the same instinct — the fresh news item is the discriminator, the rest is textbook.
Graphene is frequently in news recently. What is its importance? 1. It is a two-dimensional material and has good electrical conductivity. 2. It is one of the thinnest but strongest materials tested so far. 3. It is entirely made of silicon and has high optical transparency. 4. It can be used as conducting electrodes required for touch screens, LCDs and organic LEDs. Which of the statements given above are correct?
- (a) 1 and 2 only
- (b) 3 and 4 only
- (c) 1, 2 and 4 only
- (d) 1, 2, 3 and 4
Answer(c) 1, 2 and 4 only
The same material, one place down the same list — UPSC tested what graphene is and does; UPPSC tests where it sits in the chronology of new materials.
- practice — not a real PYQ
'Black gold', reported in the news in 2019, was developed by a team at which Indian institution?
- (a)Tata Institute of Fundamental Research, Mumbai
- (b)Indian Institute of Science, Bengaluru
- (c)Bhabha Atomic Research Centre, Mumbai
- (d)Indian Association for the Cultivation of Science, Kolkata
Answer(a) Tata Institute of Fundamental Research, Mumbai — the team was led by Prof. Vivek Polshettiwar, and the work was published in Chemical Science in July 2019.
- practice — not a real PYQ
Which one of the following is NOT an allotrope of carbon?
- (a)Graphene
- (b)Fullerene
- (c)Kevlar
- (d)Diamond
Answer(c) Kevlar — it is a synthetic para-aramid polymer containing carbon, nitrogen, oxygen and hydrogen, not a pure-carbon allotrope; graphene, fullerene and diamond are all allotropes of carbon.