List of top Chemistry Questions asked in CBSE CLASS XII

Arrange the following complex ions in increasing order of their crystal field splitting energy (\( \Delta_0 \)):
\(\text{[Co(NH}_3\text{)}_6]^{3+}, \, \text{[CoF}_6]^{3-}, \, \text{[Co(CN)}_6]^{3-}\)
Write the IUPAC name of the complex:
\(\text{[Co(H}_2\text{O})(\text{CN})(\text{en}_2)^{2+}]\)
Write the reaction involved in Hell-Volhard-Zelinsky reaction.
Name the reagent in the following reaction:
\( \text{CH}_3\text{CH} = \text{CH}-\text{CN} \xrightarrow{} \text{CH}_3\text{CH} = \text{CH}-\text{CHO} \)
Arrange the following in decreasing order of their acidic strength:
\( \text{CH}_3\text{COOH}, \, \text{O}_2\text{N}-\text{CH}_2\text{COOH}, \, \text{HCOOH} \)
Acetaldehyde is more reactive than acetone towards addition of HCN.
In semicarbazide, only one -NH₂ group is involved in the formation of semicarbazone.
Give simple chemical tests to distinguish between the following pairs of compounds: (1) \( \text{C}_6\text{H}_5\text{COCH}_3 \text{ and } \text{C}_6\text{H}_5\text{COCH}_2\text{CH}_3 \)
Write the major product(s) in the following reactions: 
KMnO and KOH,
What is the structural difference between nucleoside and nucleotide?
What type of linkages hold monomers of proteins together?
Give one example each for Fibrous protein and Globular protein.
What is meant by zwitter ionic form of amino acids?
What are essential amino acids?
In aqueous media, which is a stronger reducing agent — Cr³⁺ or Fe³⁺ and why?
Define lanthanoid contraction. How does it affect the atomic radii of the third transition series and the second transition series?
What is the cause of contraction in the atomic size of lanthanoids?
Why do transition metals and their compounds act as good catalysts?
How will you bring about the following conversions? (any three)
Benzoic acid to Benzaldehyde
Ethanal to Propanone
(c) Acetophenone to Benzoic acid
(d) Bromobenzene to 1-Phenylethanol
Give the structures of A, B, and C in the following reactions:
Fe/HCl.NaNO2+HCl
Give the structures of A, B, and C in the following reactions:
KCN.LiAlH4
Name the reagent used in the bromination of phenol to form 2,4,6-Tribromophenol.
Write the reactions involved in the following:
(i) Reimer-Tiemann reaction
(ii) Kolbe’s reaction
What happens when chlorobenzene and methyl chloride are treated with sodium metal in dry ether?
Why does the presence of nitro groups at ortho- and para- positions in haloarenes increase their reactivity towards nucleophilic substitution reactions?