List of top Questions asked in CBSE CLASS XII- 2025

Write the full form of PEM and describe it briefly.
Differentiate between underweight and wasting.
A student is curious to learn about the major developments in food processing and technology that occurred before the 20th century. In this context, name two researchers who made a significant contribution in those times. Also name the process developed by each one of them.
How is ironing different from hot pressing of clothes? Give any two differences.
By using different types of lines in various combinations on fabrics, name four basic groups of shapes which can be formed?
What is meant by food fortification? Give its two examples.
Few children of a village have become victims of a natural calamity and are without home. Besides these, which other four types of vulnerable children need care and protection?
A doctor has diagnosed a fall in haemoglobin levels of an adolescent girl. Which nutritional deficiency disorder does it indicate? List any two other symptoms which may be seen in her in this disorder.
Why is the ability of oxygen greater than fluorine to stabilise higher oxidation states of transition metals?
How do you prepare potassium manganate from pyrolusite ore?
Out of KMnO$_4$ and K$_2$MnO$_4$, which one is paramagnetic and why?
Write the reaction of D-Glucose with the following:
(a) HCN (b) Br$_2$ water (c) (CH$_3$CO)$_2$O
Write two differences between DNA and RNA.
Why is molecularity applicable only for elementary reactions and order is applicable for elementary as well as complex reactions?
Why can azeotropic mixture not be separated by fractional distillation?
Assertion (A): First ionisation enthalpy of Cr is lower than that of Zn.
Reason (R): Zinc is a non-transition element.
With increase in atomic number, the melting point of transition metals :
Write the reaction involved in the following :
Clemmensen reduction
An organic compound (X) having molecular formula C$_5$H$_{10$O can show various properties depending on its structures. Draw each of the structures if it :
shows Cannizzaro reaction.
Answer the following question:
Name two elements of 3d series for which the third ionisation enthalpies are quite high.
Complete the following ionic equations :
5SO$_3^{2-}$ + 2MnO$_4^-$ + 6H$^+$ ⟶ ?
Account for the following :
(I) The E$^\circ_{Mn^{2+}/Mn}$ value for manganese is highly negative, whereas E$^\circ_{Mn^{3+}/Mn^{2+}}$ is highly positive.
Calculate the emf of the following cell at 25$^\circ$C :
Zn(s) $\mid$ Zn$^{2+}$ (0.1 M) $\parallel$ H$^+$ (0.01 M) $\mid$ H$_2$(g) (1 bar), Pt(s)
Given: E$^\circ_{Zn^{2+}/Zn}$ = –0.76 V, E$^\circ_{2H^+/H_2}$ = 0.00 V, log 10 = 1
How can you convert propanenitrile to 1-aminopropane?

Write structure of the products of the following reactions: