<u>Answer:</u> The mass of solid NaOH required is 80 g
<u>Explanation:</u>
Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

where,
n = acidity for bases = 1 (For NaOH)
Molar mass of NaOH = 40 g/mol
Putting values in above equation, we get:

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.
Mathematically,

Or,
......(1)
We are given:
Given mass of NaOH = ?
Equivalent mass of NaOH = 40 g/eq
Volume of solution = 400 mL
Normality of solution = 5 eq/L
Putting values in equation 1, we get:

Hence, the mass of solid NaOH required is 80 g
Two or more compounds that have same molecular formula but differ in the arrangement of atoms in molecule and thus posses different properties are known as isomers.
The molecular formula of pentane is
substituting one hydrogen from pentane with bromine results in the formation of monobromo derivatives of pentane having molecular formula,
.
The structure of monobromo derivatives of pentane that is 1-bromopentane, 2-bromopentane, and 3-bromopentane and having molecular formula,
is shown in the image.
The other two arrangements of monobromo derivatives of pentane that is 2-bromo-2-methylbutane and 2-bromo-3-methylbutane is shown in the image.
There are different structures of monobromo derivatives of pentane having molecular formula,
which contain a 4-carbon chain are 1- bromo-2-methylbutane and 1-bromo-3-methylbutane shown in the image.
Diffusion is the process of a substance spreading out to evenly fill its container or environment. Rate of diffusion of a gas is inversely proportional to the molar mass of the gas.

Lighter(lower) the molar mass of the gas , faster will be its rate of diffusion and heavier (higher) the molar mass of the gas , slower will be its rate of diffusion.
We have to arrange the given gases from slowest rate of diffusion to fastest rate of diffusion that means we need to arrange gases from higher molar mass to lower molar mass.
Molar mass of given gases are :
Cl = 35.5 g/mol
Xe = 131.29 g/mol
He = 4.00 g/mol
N = 14.00 g/mol
So correct order for slowest rate of diffusion (highest molar mass) to fastest rate of diffusion (lowest molar mass) is :
Xe , Cl , N , He
Xe having the highest molar mass will have the slowest rate of diffusion and He with lowest molar mass will have the fastest rate of diffusion, so option 'c' is correct.
Note : Slowest rate of diffusion = High Molar Mass
Fastest rate of diffusion = Low Molar Mass
Answer:
Explanation:
The chemical equation is:
There are several definitions of acid and bases: Arrhenius', Bronsted-Lowry's and Lewis'.
Bronsted-Lowry model defines and <em>acid</em> as a donor of protons, H⁺.
In the given equation HNO₃ is such substance: it releases an donates its hdyrogen to form the H₃O⁺ ion.
On the other hand, a <em>base</em> is a substance that accepts protons.
In the reaction shown, H₂O accepts the proton from HNO₃ to form H₃O⁺.
Thus, H₂O is a base.
In turn, on the reactant sides the substances can be classified as acids or bases.
H₃O⁺ contain an hydrogen that can be donated and form H₂O; thus, it is an acid (the conjugated acid), and NO₃⁻ can accept a proton to form HNO₃; thus it is a base (the conjugated base).
Answer:
The correct answer is: Serine, Histidine, Aspartate
Explanation:
The catalytic triad of an enzyme is composed of three aminoacid residues which are the most important for its catalytic activity. They are located in the catalytic site of the enzyme. In the case of chymotrypsin- a serine protease, the catalytic triad is composed by serine, histidine and aspartate (Ser-His-Asp). Serine proteases hydrolyse peptidic bonds in proteins and peptides. To do that, the histidine-which interacts with the aspartate by a hydrogen bond so its pKa increases- take a proton from the serine. Thus, deprotonated serine is able to attack the peptide bond and to perform hydrolysis.