CBSE 12TH CHEMISTRY - Online Test
Q1. Two nucleic acid chains are wound about each other and held together by hydrogen bonds between pairs of bases is called
Answer : Option D
Explaination / Solution:
Secondary structures are hydrogen pairs of bases.
Q2. Which of the following compounds will react with sodium hydroxide solution in water?
Answer : Option B
Explaination / Solution:
Phenol is more soluble in NaOH than in water is because phenol is slightly more acidic than alcohols. The Ka for phenol in water is 1e-10 which is not very strong. But by mixing with NaOH, it causes the phenol to release the H+ to form sodium phenoxide.
Q3. Which of the following has highest boiling point?
Answer : Option A
Explaination / Solution:
i=3 so ΔTb will be maximum and hence Tb will be maximum.
Q4. Which of the following is an intermediate in the mechanism for amide synthesis through acylation o
Answer : Option C
Explaination / Solution:
- A is the intermediate formed by nucleophilic attack by CH3NH2 on carbonyl carbon of CH3COCl.
Q5. Blister copper is about
Answer : Option D
Explaination / Solution:
Blistter Cu is 98% Cu.
Q6. Iodine is liberated from KI solution when treated with
Answer : Option D
Explaination / Solution:
Cu_2+ will reduce to Cu + and I- will oxidize to I2.
Q7. Frenkel defects are not found in alkali metal halides because
Answer : Option C
Explaination / Solution:
Alkali metals have frenkel defect because of there large size.
Q8. Hexamethylenediamine with adipic acid to manufacture Nylon 6, 6 needs the following conditions to proceed.
Answer : Option A
Explaination / Solution:
Formation of Nylon 6,6 is done at high Pressure and high temperature.
Q9. Which is least soluble in water?
Answer : Option C
Explaination / Solution:
Ag2S is least soluble in water.
Q10. In Hell – Volhard Zelinsky reaction, the reagents used are
Answer : Option C
Explaination / Solution:
In HVZ we use X2 in presence of Red P4 .
