<u>Answer:</u> The average rate of the reaction is 
<u>Explanation:</u>
To calculate the molarity of hydrogen gas generated, we use the equation:

Moles of hydrogen gas = 
Volume of solution = 250 mL = 0.250 L (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:

Average rate of the reaction is defined as the ratio of concentration of hydrogen generated to the time taken.
To calculate the average rate of the reaction, we use the equation:

We are given:
Concentration of hydrogen generated = 0.1564 M
Time taken = 20.0 minutes
Putting values in above equation, we get:

Hence, the average rate of the reaction is 
Answer:
acid
Explanation:
Methyl acetate, also known as MeOAc, acetic acid methyl ester or methyl ethanoate, is a carboxylate ester with the formula CH3COOCH3. It is a flammable liquid with a characteristically pleasant smell reminiscent of some glues and nail polish removers.
Answer: Option (2) is the correct answer.
Explanation:
Atomic number of oxygen atom is 8 and its electronic distribution is 2, 6. So, it contains only 2 orbitals which are closer to the nucleus of the atom.
As a result, the valence electrons are pulled closer by the nucleus of oxygen atom due to which there occurs a decrease in atomic size of the atom.
Whereas atomic number of sulfur is 16 and its electronic distribution is 2, 8, 6. As there are more number of orbitals present in a sulfur atom so, the valence electrons are away from the nucleus of the atom.
Hence, there is less force of attraction between nucleus of sulfur atom and its valence electrons due to which size of sulfur atom is larger than the size of oxygen atom.
Thus, we can conclude that the oxygen atom is smaller than the sulfur atom because the outer orbitals of oxygen are located closer to the nucleus than those of sulfur.
The mass of a substance per unit volume is the substance's density.
D = m/v.