MHT CET 2020 :: Chemistry :: General questions

• Chemistry - General questions

 Which among the following compound is not optically active?

Answer:

Explanation:

 3- chloropentane compound is not optically active

Because in this compound no stereogenic centre is present and they are superimposable on each other. So, in the molecule absence of stereogenic centre shows that this molecule is not optically active.

 An element crystallises in a bcc lattice with cell edge of 500 pm. The density of the element is 7.5 g cm^-3. How many atoms are present in 300g of metal?

Answer:

Explanation:

 Given ,

 edge length

 (a)= 500 pm= 500 x 10^-12 m= 5 x 10^-8 cm

 Density (d) =7.5 g cm^-3

 Mass (m) = 300 g

 For bcc unit , Z=2

 the volume of unit cell (a³ )

 $=(5\times 10^{-8}cm)^{3}=1.25 \times 10^{-22}cm^{3}$

 Volume occupied by each atom

$\frac{1.25\times 10^{-22}cm^{-3}}{2}=6.25\times 10^{-23}cm^{-3}$

 Volume of sample = $\frac{mass}{density}=\frac{300g}{7.5 gcm^{-3}}=40 cm^{3}$

 The number of atoms present in 300g of the element

   = $\frac{40 cm^{3}}{6.25\times 10^{-23}cm^{3}}=6.4\times 10^{23}atoms$

 What is IUPAC name of hydroquinone?

Answer:

Explanation:

 Benzene-1, 4-diol is IUPAC  name of hydroquinone 

 The equilibrium constant  for a reaction is 20. what is the value of  $\triangle G^{0}$ at 300 K ? (R=8 x 10^-3 kJ)

Answer:

Explanation:

 Given,

 K_eq =20

 temperature (T)=300 K

 R= 8 x10^-3 kJ

 we have,  $\triangle G^{0}$=-2.303 x R xT x log K_eq

 = $-2.303 \times8\times 10^{-3}\times\log 20\times300 (\log 20=1.301)$

   = 7.191 k J /mol

An acyl chloride is hydrogenated over catalyst palladium on barium sulphate to form an aldehyde. This reaction  is called as

Answer:

Explanation:

 When acyl chloride is hydrogenated over catalyst palladium on barium sulphate to form an aldehyde.

 This reaction is called Rosenmund reduction.

 It is a hydrogenation process in which are acyl chloride selectively reduced to an aldehyde

• Chemistry - General questions