Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

What is the oxidation state of phosphorus in the following:

POF₃

Write names and chemical formulae of monomers used in preparing Buna-N.

Calculate the degree of dissociation (α) of acetic acid if its molar conductivity (Λ_m) is 39.05 S cm² mol⁻¹.

(Given \[\ce{\lambda^{\circ}_{(H^+)}}\] = 349.6 S cm² mol⁻¹ and \[\ce{\lambda^{\circ}_{(CH_3COO^-)}}\] = 40.95 S cm² mol⁻¹)

30 g of urea (M = 60 g mol⁻¹) is dissolved in 846 g of water. Calculate the vapour pressure of water for this solution if vapour pressure of pure water at 298 K is 23·8 mm Hg.

Predict the products of the following reactions :

Predict the products of the following reactions :

Account for the following :

Bond angle in NH+4NH4+ is higher than NH₃.

Define the following terms :

Limiting molar conductivity

State Raoult's law for the solution containing volatile components. What is the similarity between Raoult's law and Henry's law?

Draw the structures of the following compounds :

 N₂O₅

Write balanced chemical equations involved in the following reactions: 
Calcium phosphide is dissolved in water. 

 How can you determine limiting molar conductivity,   0 m for strong electrolyte and weak electrolyte?

 An element crystallises in bcc lattic with a cell edge of 3 × 10^-8cm. The density of the element is 6.89 g cm^-3 . calculate the molar mass of element. (N_A = 6.022 × 10²³ mol^-1)

Write the structure of the monomer used in the following polymer:
Buna-S

 Predict the main product of the following reaction:\[\begin{array}{c}
\ce{O\phantom{----}O\phantom{-}}\\
\ce{||\phantom{----}||\phantom{-}}\\
\ce{CH3-C-CH2-C-OCH3}
\end{array}\ce{->[(i)NaBH4][(ii)H+]}\]

Write chemical equation of the following reaction : 
Acetophenone is treated with `("Zn"("Hg"))/"Conc.HCl"`.

A steady current of 2 amperes was passed through two electrolytic cells X and Y connected in series containing electrolytes FeSO₄and ZnSO₄ until 2.8g of Fe deposited at the cathode of cell X. How long did the current flow? Calculate the mass of Zn deposited at the cathode of cell Y. 
(Molar mass: Fe=56g mol^-1,Zn=65.3g mol^-1,1F=96500C mol^-1)

In the plot of molar conductivity (∧_m) vs square root of concentration (c^1/2) following curves are obtained for two electrolytes A and B : 

Answer the following:
(i) predict the nature of electrolytes A and B.
(ii) What happens on the extrapolation of ∧_m to concentration approaching for electrolytes A and B?

Write the structure of main compounds A and B in the following reaction:
 

What is the role of Sulphur in the vulcanization of rubber?