CBSE 12TH CHEMISTRY - Online Test
Q1. An example of autocatalysis is
Answer : Option A
Explaination / Solution:
Oxidation of oxalic acid by acidified KMnO4 is example of autocatalysis.
Q2. hydrolysis of starchyields
Answer : Option A
Explaination / Solution:
Hydrolysis of starch give glucose.
Q3. Primary alcohols are prepared by reduction of carboxylic acids. Though lithium aluminium hydride is a strong reducing agent, it is not used in the reaction. Because
Answer : Option C
Explaination / Solution:
Carboxylic acids are reduced to primary alcohols in excellent yields by lithium aluminium hydride, a strong reducing agent.
However, LiAlH4 is an expensive reagent, and therefore, used for preparing special chemicals only. Commercially, acids are reduced to alcohols by converting them to the esters followed by their reduction using hydrogen in the presence of catalyst (catalytic hydrogenation).
Q4. Hinsberg’s reagent reacts with primary and secondary amines to form sulphonamides. This reagent is also known as
Answer : Option C
Explaination / Solution:
this is benzenesulphonyl chloride or hinsberg reagent.
Q5. Two solutions have different osmotic pressures. The solution of higher osmotic pressure is called
Answer : Option B
Explaination / Solution:
Hypertonic solutions are having high Osmotic Pressure.
Q6. One of the following is a fibre.
Answer : Option A
Explaination / Solution:
Polyamide is also a fibre.
Q7. Which allotrope of phosphorous is most stable?
Answer : Option A
Explaination / Solution:
Black Phosphorus is most stable isotope of phosphorus because it is highly polymerized form of phosphorous.
Q8. Gravity separation technique is mainly applicable to
Answer : Option B
Explaination / Solution:
Gavity separation is done maily for oxide ores.
Q9. Maximum magnetic moment is shown by
Answer : Option D
Explaination / Solution:
Magnetic moment is maximum for the element having maximum unpaired electrons.
Q10. The oxidation of toluene to benzoic acid can be stopped at the aldehyde stage. to give benzadehyde, The reagent used for the purpose is one of the following.
Answer : Option B
Explaination / Solution:
This is Etard Reaction.
