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

Observe the graph shown in figure and answer the following questions:

1. What is the order of the reaction?
2. What is the slope of the curve?
3. Write the relationship between k and t_1/2 (half life period).

What happens when propanone is treated with CH₃MgBr and then hydrolysed?

What happens when ethanal is treated with excess ethanol and acid?

Which will undergo faster nucleophilic addition reaction?

Acetaldehyde or Propanone

The slope in the plot of ln[R] vs. time for a first order reaction is ______.

Which of the following is most reactive in nucleophilic addition reactions?

Draw the geometrical isomers of [Co(en)₂Cl₂]²⁺. Which geometrical isomer of [Co(en)₂Cl₂]²⁺ is not optically active and why?

The following questions are case-based questions. Read the passage carefully and answer the questions that follow:

Answer the following:

(a) Write the name of the product when an aldehyde reacts with excess alcohol in the presence of dry HCl. (1)

(b) Why carboxylic acid is a stronger acid than phenol? (1)

(c) (i) Arrange the following compounds in increasing order of their reactivity towards CH₃MgBr: (1)

CH₃CHO, \[\begin{array}{cc}
\ce{(CH3)3C-C-CH3}\\
\phantom{....}||\\
\phantom{....}\ce{O}
\end{array}\],  \[\begin{array}{cc}
\ce{CH3-C-CH3}\\
||\\
\ce{O}
\end{array}\]

(ii) Write a chemical test to distinguish between propanal and propanone. (1)

OR

(c) Write the main product in the following: (2)

(i)
(ii)

Arrange the following in increasing order of their boiling point:

C₂H₅OH, C₂H₅NH₂, (C₂H₅)₃N

Aldehydes and ketones react with hydroxylamine to form ______.

The slope in the plot of `log  ["R"]_0/(["R"])` Vs. time for a first-order reaction is ______.

When D-glucose reacts with HI, it forms ______.

Solubility of gas in liquid decreases with increase in ______.

Which of the following molecules has a chiral centre correctly labelled with an asterisk (*)?

Assertion (A): Trans [CrCl₂(ox)₂]³⁻ shows optical isomerism.

Reason (R): Optical isomerism is common in octahedral complexes involving didentate ligands.

Give the reaction of glucose with hydrogen cyanide. Presence of which group is confirmed by this reaction?

Give a reason for the following observations:

Penta-acetate of glucose does not react with hydroxylamine.

In which of the following solvents, the \[\ce{C4H8NH3+X–}\] is soluble?

Radioactive decay follows first-order kinetics. The initial amount of two radioactive elements X and Y is 1 gm each. What will be the ratio of X and Y after two days if their half-lives are 12 hours and 16 hours respectively?

Out of p-tolualdehyde and p-nitrobenzaldehyde, which one is more reactive towards nucleophilic addition reactions, why?