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Answer: (4) 
Explanation:-
According to Arrhenius concept, a base is defined as a substance which donates hydroxide ions
when dissolved in water and an acid is defined as a substance which donates hydronium ions
in water.
1.
is a strong electrolyte and thus dissociate in water.
2.
is a non electrolyte and thus do no dissociate in water.

3.
is a strong electrolyte and thus dissociate in water.

4.
is a weak electrolyte and thus partially dissociate in water.

Answer:
Because if you use pen, your chromatography will separate also the colors of the pen and not just your sample.
Explanation:
The pencil since is carbon as simple element, is solid and is not dissolved in solvents like commonly are used in paper chromatography, it will not interrupt the separation of the compounds in your mixture, otherwise, your results will be confuse because you are not sure if the spots that you observe is due to the ink pen or due to the mixture that you want to separate.
C
because the mass never changes, it is always equal on both sides.
Answer:

Explanation:
Hello,
In this case, since the molarity is computed by:

Whereas the solute is the hydrochloric acid, we compute the corresponding moles with its molar mass (36.45 g/mol):

Next, since the solution contains both HCl and water, we compute the volume in liters by using its density:

Therefore, the molarity turns out:

Regards.