List of top Questions asked in CBSE Compartment Exam Class XII

The most stable complex among the following is:
The standard electrode potential for Sn\(^{4+}\)/Sn\(^{2+}\) couple is \(+0.15\ \text{V}\) and for Cu\(^{2+}\)/Cu couple is \(+0.73\ \text{V}\). These two couples are connected to make an electrochemical cell. The redox reaction is spontaneous. The cell potential will be:
Calculate the molality of a solution prepared by dissolving 5 g of NaOH in 450 g of water. (Molar mass of NaOH = 40 g/mol)
Y Ltd. issued 1,000 debentures of Rs 100 each at par, redeemable at a premium of 10 percent. Pass journal entries for issue and redemption.
X Ltd. issued 10,000 equity shares of Rs 10 each at a premium of Rs 2 per share. Amount payable: Rs 4 on application, Rs 5 on allotment (including premium), and Rs 3 on first & final call. All shares were subscribed and money received. Pass journal entries.
From the following details, calculate Cash Flow from Investing Activities: - Purchase of Machinery Rs 1,50,000
- Sale of Land Rs 80,000
- Purchase of Investments Rs 50,000
- Interest received Rs 8,000
Calculate the packing efficiency in a face-centered cubic (FCC) crystal.
Write the IUPAC name of the compound: \[ \text{CH}_3-CH_2-CH(CH_3)-CH_2-CH_2-CH_3 \]
Write balanced chemical equations for the following:
(a) Reaction of white phosphorus with chlorine
(b) Reaction of orthophosphoric acid on heating
Calculate the EMF of the cell:
Zn(s) | Zn\(^{2+}\) (0.1 M) || Cu\(^{2+}\) (1.0 M) | Cu(s)
Given: \( E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76\,V \), \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.34\,V \)
A parallel plate capacitor is charged to potential \( V = 300\,V \) and then disconnected from the battery. If the separation between the plates is doubled, what will be the new potential difference across the plates?
A convex lens of focal length \( f = 15\,cm \) forms a real image of a 6 cm tall object placed at 30 cm. Find the position, nature, and height of the image.
The half-life of a radioactive element is 10 minutes. Find the time in which its activity reduces to 1/16 of the original.

A manufacturer makes two types of toys A and B. Three machines are needed for production with the following time constraints (in minutes): \[ \begin{array}{|c|c|c|} \hline \text{Machine} & \text{Toy A} & \text{Toy B} \\ \hline M1 & 12 & 6 \\ M2 & 18 & 0 \\ M3 & 6 & 9 \\ \hline \end{array} \] Each machine is available for 6 hours = 360 minutes. Profit on A = Rupee 20, on B = Rupee 30.
Formulate and solve the LPP graphically.

Evaluate the definite integral: \[ \int_0^{\frac{\pi}{2}} \frac{\sin x}{1 + \cos^2 x} \, dx \]
A die is thrown three times. Find the probability of getting a number greater than 4 at least once.
Find the shortest distance between the lines: \[ \frac{x - 1}{2} = \frac{y + 1}{3} = \frac{z}{4}, \quad \frac{x + 2}{1} = \frac{y - 3}{-2} = \frac{z + 1}{2} \]
The cost and revenue functions are given as: \[ C(x) = 3x^2 + 5x + 200, \quad R(x) = 50x \] Find the number of items that should be sold to maximize the profit.
What type of cell is mercury cell? Why is it more advantageous than dry cell?

The standard electrode potential for Ni²⁺/Ni couple is -0.25 V and for Ag⁺/Ag couple is 0.80 V. These two couples are connected to make an electrochemical cell. The redox reaction is spontaneous. The cell potential will be:

Assertion (A): Quadrilateral formed by vertices A(0, 0, 0), B(3, 4, 5), C(8, 8, 8) and D(5, 4, 3) is a rhombus.
Reason (R): ABCD is a rhombus if $AB = BC = CD = DA$, and $AC \ne BD$.
If A is a square matrix of order 3 and $|A| = 6$, then the value of $|\text{adj} A|$ is:
If ABCD is a parallelogram and AC and BD are its diagonals, then $\overrightarrow{AC} + \overrightarrow{BD}$ is:
Function f is defined as: \[ f(x) = \begin{cases} 2x + 2, & x<2 \\ k, & x = 2 \\ 3x, & x>2. \end{cases} \text{Find the value of } k \text{ for which } f \text{ is continuous at } x = 2. \]
Evaluate $\displaystyle \int \frac{\cos 2x}{\sin^2 x \cdot \cos^2 x} dx$