Class 12th

 1.80g of solute A was dissolved in 62.5cm³ of ethanol and freezing point of the solution was found to be 155.1 K . The molar mass of solute A is __________g mol^-1.

[Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g cm^-3. Freezing point depression constant of ethanol is 2.00 K kg mol^-1]

Consider a matrix A = $\left[\begin{array}{ccc}\hfill \alpha \hfill & \hfill \beta \hfill & \hfill \gamma \hfill \\ \hfill {\alpha }^2\hfill & \hfill {\beta }^2\hfill & \hfill {\gamma }^2\hfill \\ \hfill \beta +\gamma \hfill & \hfill \gamma +\alpha \hfill & \hfill \alpha +\beta \hfill \end{array}\right]$ $\begin{array}{ccc}\hfill \hfill & \hfill \hfill & \hfill \hfill \\ \hfill {}^{}\hfill & \hfill {}^{}\hfill & \hfill {}^{}\hfill \\ \hfill \hfill & \hfill \hfill & \hfill \hfill \end{array}$ , where , , $\gamma$  $$ are three distinct natural numbers.

If $\frac{det\left(adj\left(adj\left(adj\left(adjA\right)\right)\right)\right)}{{\left(\alpha -\beta \right)}^{16}{\left(\beta -\gamma \right)}^{16}{\left(\gamma -\alpha \right)}^{16}}=2^{32}*3^{16},$ $\frac{}{{}^{}{}^{}{}^{}}{}^{}{}^{}$ then the number of such 3 – tuples (, , $\gamma$ $$ ) is…………

In the below reaction, 5g of toluene is converted into benzaldehyde with 92% yield. The amount of benzaldehyde produced is____________* 10^-2 g. (Nearest integer)

The spin only magnetic moment of the complex present in Fehling's reagent is __________B.M.

(Nearest Integer)

The oxidation state of manganese in the product obtained in a reaction of potassium permanganate and hydrogen peroxide in basic medium is___________.

Among the following ores Bauxite, Siderite, Cuprite, Calamine, Haematite, Kaolinite, Malachite, Magnetite, Sphalerite, Limonite, Cryolite, the number of principal ores if iron is ___________.

A capacitor of capacitance 500 $\mu F$ is charged completely using a dc supply of 100 V. It is now connected to an inductor of inductance 50 mH to form an LC circuit. Then maximum current in LC circuit will be_______ A.

[A]               ->                     [B]

Reactant                         Product

If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is x * 10^-6 s^-1. The value of x is___________. (Nearest Integer)

When a certain amount of solid A is dissolved in 100g of water at 25°C to make a dilute solution, the vapour pressure of the solution is reduced to one-half of that of pure water. The vapour pressure of pure water is 23.76 mmHg. The number of moles of solute A added is_________.

(Nearest Integer)

Two radioactive materials A and B have decay constants 25 $\lambda$  and 16 $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of B to that of A will be “e” after a time $\frac{1}{a\lambda }.$  The value of a is__________.