New Delhi:
The Central Board of Secondary Education (CBSE) will conduct the Chemistry exam for the students of Class 12 on February 27, 2024. Students who will be appearing in the exam can check the official website of the CBSE for previous year's question papers for Chemistry. The following are high mark questions from the previous year's Chemistry board exam.
Important Chemistry questions
- a) An element has an atomic mass 93 g mol-1 and density 11.5 g cm-3. If the edge length of its unit cell is 300 pm, identify the type of unit cell.
- b) Write any two differences between amorphous solids and crystalline solids.
- a) A first order reaction takes 100 minutes for completion of 60% of the reaction. Find the time when 90% of the reaction will be completed.
- (b) With the help of diagram explain the role of activated complex in a reaction.
- The elements of 3d transition series are given as: Se Ti V Cr Mn Fe Co Ni Cu Zn
- (i) Write the element which shows maximum number of oxidation states. Give reason.
- (ii) Which element has the highest m.p.?
- (iii) Which element shows only +3 oxidation state?
- (iv) Which element is a strong oxidizing agent in +3 oxidation state and why?
- Carry out the following conversions :
- a) Ethanal to But-2-en-1-al
- b) Propanoic acid to 2-chloropropanoic acid
- Distinguish with a suitable chemical test :
- a) CH3COCH2CH3 and CH3CH2CH2CHO
- b) Ethanal and Ethanoic acid
- a)Write the structure of oxime of acetone.
- Assign reason for each of the following:
- (i) Manganese exhibits the highest oxidation state of +7 among the 3d series of transition elements.
- (ii) Transition metals and their compounds are generally found to be good catalysts in chemical reactions.
- (iii) Zn has lowest enthalpy of atomization.
- (iv) Cu+ is unstable in an aqueous solution.
