CBSE 11TH CHEMISTRY - Online Test

Answer : Option C
Explaination / Solution:

Max Planck theorized that energy was transferred in chunks known as quanta, equal to hν. The variable h is a constant equal to 6.63 × 10-34 J·s and the variable ν$\nu$represents the frequency in 1/s.

This equation allows us to calculate the energy of photons, given their frequency.

If the wavelength is given, the energy can be determined by first using the wave equation(c=λ×ν)to find the frequency, then using Planck’s equation to calculate energy.

Answer : Option D
Explaination / Solution:

Acid rain does not cause Global warming as it does not release any greenhouse gas in the atmosphere.

Answer : Option B
Explaination / Solution:

Hydrogen, like the halogens, has one electron short of a complete outer shell and can form H- ions like Cl- and therefore forms ionic compounds with reactive metals – NaH similar in structure to NaCl. Hydrogen can gain one electron to form a duplet.Hydrogen also exists as a diatomic gas like fluorine and chlorine.

Answer : Option D
Explaination / Solution:

• n XeF​​​​2: Xe has 2 of its electrons in bonding with F. So, since Xe has 8 valence electrons,  the no.of lone pairs = no. of non−bonding electrons2=62=3
  
• In XeO3: Xe has 6 of its electrons in bonding with O (bcoz of double bond). So, Xe will have 2 non bonding electrons and therefore 1 lone pair.
• In XeF4: Xe has 4 of its electrons in bonding with F. So, Xe will have 4 non bonding electrons and therefore 2 lone pairs.
• In XeF6: Xe has 6 of its electrons in bonding with F. So, Xe will have 2 non bonding electrons and therefore 1 lone pair.

So XeF2 has the maximum no. of lone pairs associated with Xe.

Answer : Option A
Explaination / Solution:

NaHCO3 is baking soda.

Answer : Option C
Explaination / Solution:

they are aromatic heterocyclic compounds (furan, thiophene and pyridinr respectively).

Answer : Option A
Explaination / Solution:

3g/dm3

Answer : Option D
Explaination / Solution:

Acidity of BF3is explained on the basis of Lewis concept because Boron have vacant p-orbital.

Answer : Option A
Explaination / Solution:

Alkali metals have +1 oxidation state. Because they have only one electron in their outer most shell and by losing that one they can achieve stable configuration, that's why they have +1 oxidation state.

Answer : Option C
Explaination / Solution:

The problem is based upon the concepts of Avogadro's law

.Accordingly   ,  one mole  (ie  18 g )  of water   contains  

 = 6.02 x 1023 molecules of water

. Again , since the number of  oxygen atoms in one molecule of water ( H2 O ) 

 =    1  atom 

∴$\therefore$ the number of oxygen atoms in 6.02  x 1023 molecules of water

.=    6.02 x 1023   atoms