MHT CET 2018 :: Chemistry :: General questions

• Chemistry - General questions

Molarity is

Answer:

Explanation:

Molarity  is defined as the number of moles of solute dissolved in one litre  or one dm³  volume of solution.It is expressed by the symbol 'M'

Molarity (M) = Number of molesof solute/ Volume of solution(in L or dm³)

Which carbon  atom of deoxyribose sugar in DNA   does not contain 

 bond?

Answer:

Explanation:

 Deoxyribose is a pentose sugar with five carbon atoms. The four carbon atoms of the ring are numbered 1'.2',3' and 4' . The carbon atom of  -CH₂OH  is numbered 5'. These are three-OH groups at position 1',3' and 5'. Hydrogen  atoms  are attached to carbon atoms 1',2' ,3' ,4' and 5'. Only carbon atom at C₂ of deoxyribose sugar in DNA  does not contain -C-OH bond.

Note: The prefix 2'-deoxy means that oxygen is missing from the 2' position of ribose.

 The molarity of urea (molar mass 60g  mol^-1) solution by dissolving 15 g of urea in 500 cm³ of water is

Answer:

Explanation:

Given, mass of urea =15 g

 Molar mass of urea = 60 g mol^-1

 Volume = 500 cm³= 500 mL=0.5 L                 $\begin{bmatrix}\because 1 cm^{3} & =1mL \\1L & =1000mL \end{bmatrix}$

 $\therefore$  Molarity=

                Mass of solute in grams (w) / Molar mass of solute(M) x volume of solutionV(L)

 Molarity of urea= $\frac{15 g}{60g mol^{-1}\times0.5 L}$

  $\Rightarrow 0.5 mol/L=0.5 mol/dm^{2}$     $ (\because 1L=1dm^{2})$

What  is the catalyst  used for oxidation of SO₂ to SO₃ in lead chamber process for manufacture of sulphric acid?

Answer:

Explanation:

In the lead chamber process, a mixture containing  SO₂, air NO is treated with steam(H₂O ).

In this creation,NO (nitric oxide)act as a catalyst.

In this reaction, NO (niric oxide) acts as a catalyst.

$2SO_{2}+O_{2}+2H_{2}O+[NO]\rightarrow 2H_{2}SO_{4}+[NO]$

           (from air)             (catalyst)                 catalyst

Which symbol replaces the unit of atomic mass, amu?

Answer:

Explanation:

 Presently the new symbol used is 'u' (known as unified mass)  in place of amu. It is defined as mass exactly equal to 1/12th mass of one C-12 atom

• Chemistry - General questions