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If your Class 12 chapter on the d- and f-block elements ends with a list of uses, this is the list you are expected to know. Below, each use from the NCERT Class 12 chemistry chapter is tied to the property that explains it, with current production numbers and a short drill to make it stick.
Why are transition metals so useful in industry?
Two properties do most of the work. The first is alloys. The NCERT chapter notes that alloys form readily between atoms whose metallic radii are within about 15 percent of each other, which is why chromium, vanadium, tungsten, molybdenum and manganese go into so many steels. The strong metallic bonding behind this is the same story told in our post on why transition metals have high melting points, but zinc doesn't.
The second is catalysis. NCERT ascribes the catalytic activity of transition metals to their ability to adopt multiple oxidation states and to form complexes. At a solid surface, reactants bond to metal atoms, which concentrates them and weakens their bonds, so the activation energy falls. For what that does to the rate, read how many times the rate rises when a catalyst lowers activation energy.
Why do iron and steel come first?
NCERT says it plainly: "Iron and steels are the most important construction materials." Making them means reducing iron oxides, removing impurities, and adding carbon and alloying metals such as Cr, Mn and Ni (NCERT, section 4.7).
Total world crude steel production was 1,849.4 million tonnes (Mt) in 2025, according to the World Steel Association. India produced 164.9 Mt in 2025, up 10.4% on 2024, second only to China's 960.8 Mt.
What is titanium dioxide used for?
Titanium dioxide (TiO2) is the white pigment in everyday products. The US Geological Survey's Mineral Commodity Summaries 2026 chapter on titanium lists the leading uses of TiO2 pigment, in descending order, as paints, plastics and paper. The same chapter estimates world TiO2 pigment capacity at 9,900,000 tonnes a year at the end of 2025, with India at 91,000 tonnes.
In NCERT's table of ion colours, Ti4+ has a 3d0 configuration and is colourless. With no d electrons there is no d-d transition to absorb visible light, which fits a pigment that looks white.
Which transition metal catalysts should you know?
These five come straight from NCERT sections 4.3.12 and 4.7 in the d- and f-block chapter:
V2O5 catalyses the oxidation of SO2 in the contact process for sulphuric acid.
Finely divided iron catalyses the Haber process, making ammonia from N2 and H2.
Nickel catalysts allow the hydrogenation of fats.
TiCl4 with Al(CH3)3 forms the Ziegler catalysts used to make polythene.
PdCl2 is the catalyst NCERT lists for the Wacker process, which makes ethanal.
What are lanthanoids used for?
NCERT's answer starts with steel: "The best single use of the lanthanoids is for the production of alloy steels for plates and pipes." Misch metal is about 95% lanthanoid metal and 5% iron, with traces of S, C, Ca and Al, and a good deal of it goes into a magnesium-based alloy for bullets, shells and lighter flints (NCERT, section 4.5). Mixed lanthanoid oxides catalyse petroleum cracking, and some individual lanthanoid oxides are phosphors in television screens and similar fluorescing surfaces.
The market picture is wider than the syllabus. The USGS rare earths chapter prices a commercial mischmetal grade of 65% cerium and 35% lanthanum, and estimates that the leading global use of rare earths, the group that includes the lanthanoids, was magnets. If the +2 and +4 exceptions in this series confuse you, see why Ce4+ is oxidising and Eu2+ is reducing.
How do you remember the applications for the exam?
Learn each use from the NCERT chapter as one line with four parts: the job, the substance, the oxidation state of the metal, and the reason it works. Working out the oxidation state turns a memorised list into chemistry you can rebuild.
Sulphuric acid (contact process): V2O5, vanadium +5, because 2x + 5(-2) = 0. It works because vanadium can switch oxidation states.
Ammonia (Haber process): finely divided Fe, oxidation state 0. It works by bonding reactants at its surface.
Hydrogenating fats: Ni, oxidation state 0. Same surface idea.
White paint: TiO2, titanium +4, configuration 3d0. No d-d absorption of visible light, consistent with a white pigment.
Lighter flints: misch metal in a magnesium-based alloy. Mostly lanthanoid metal with about 5% iron.
Phosphors: some individual lanthanoid oxides, typically Ln2O3, lanthanoid +3. NCERT calls +3 the most stable oxidation state of all the lanthanoids.
Cover everything after the job and recall the rest.
If the oxidation-state arithmetic trips you up, the Fermi Problem Library has worked problems with a step-by-step solver that explains the reasoning rather than printing an answer. For gaps in the theory behind a line, such as why a 3d0 ion is colourless, the Fermi Concept Library gives every chemistry concept its own lesson and its place in the map.
Run the six-line drill once tonight, then try it again from memory tomorrow.
