Chemistry Mcqs

Element that have same number of neutrons are called__________?A. isotope
B. isobar
C. isotone
D. None of these

 

Calculate % of N in KNO3__________?

A. 14.34%
B. 18.56%
C. 13.86%
D. None of these

The pH of milk is_______?A. 9
B. 6.5-7
C. 8
D. 12

 

The process in which solid changes directly into vapours without passing through liquid state?A. Decantation
B. Sublimation
C. Evaporation
D. None

 

The Boiling Point of Ethyl Alcohol is_________?A. 78°C
B. 58°C
C. 73°C
D. 56°C

 

Why does Ethyl Alcohol show high boiling point then Acetone?A. Due to Hydrogen bonding
B. Due to high molecular weight
C. Due to its Acidic nature
D. Due to its Low molecular weight

 

Why do we determined the boiling point of a liquid?A. To check its Acidity and Basicity
B. To Check temperature
C. To check its Purity and nature
D. None of These

 

Which of the following can be separated by ” Sublimation Method”?A. Sand and Iron Filing
B. Sand and Naphthalene
C. Both A & B
D. None

 

The Chemical Formula of Sand is___________?A. Si2O3
B. SiO2
C. Al2O3
D. Sr2O

The chemical compound silicon dioxide, also known as silica (from the Latin silex), is an oxide of silicon with a chemical formula of SiO2 and has been known for its hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms.

 

Benzene gives mainly_________?

A. Addition reaction
B. Substitution reactions
C. Halogenation
D. All of these

enzene is much more stable than expected.
The extra stability means that benzene will less readily undergo addition reactions. In benzene, the π-electrons are delocalised and makes the structure more stable. Thus, benzene does not give addition reactions because of resonance stabilisation.
The more loosely held electrons are open to attack by electrophiles. Hence, the characteristic reaction of benzene is electrophilic substitution.
Example: Nitration and Suphonation of Benzene. So it does not undergo Elimination reaction.