<u>Answer:</u> The number of
ions dissociated are
<u>Explanation:</u>
We are given:
pH = 2.07
Calculating the value of pOH by using equation, we get:

To calculate hydroxide ion concentration, we use the equation to calculate pOH of the solution, which is:
![pOH=-\log[OH^-]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%5BOH%5E-%5D)
We are given:
pOH = 11.93
Putting values in above equation, we get:
![11.93=-\log[OH^-]](https://tex.z-dn.net/?f=11.93%3D-%5Clog%5BOH%5E-%5D)
![[OH^-]=10^{-11.93}=1.17\times 10^{-12}M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D10%5E%7B-11.93%7D%3D1.17%5Ctimes%2010%5E%7B-12%7DM)
To calculate the number of moles for given molarity, we use the equation:

Molarity of solution = 
Volume of solution = 1243 mL = 1.243 L (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:

According to mole concept:
1 mole of a compound contains
number of particles
So,
number of
will contain =
number of ions
Hence, the number of
ions dissociated are
Molality can be expressed by moles of solute over
kilograms of solvent. The question asks the molality of 0.25m NaCl. 0.25m NaCl
is equal to 0.25 moles of NaCl over 1 kg of water.
Therefore option c , i.e. The substances in both test tubes are reactive only at high temperatures. is the only statement which is NOT supported by the student's observations.
<h3>What is the reaction between Magnesium and Hydrogen ?</h3>
Magnesium reacts with hydrochloric acid to produce hydrogen gas
Mg (s) + 2 HCl (aq) → MgCl₂ (aq) + H₂ (g)
In this reaction, the magnesium and acid are gradually used up , which can be seen in the test tube 2 .
A chemical reaction is taking place in Test tube 2 ,
Hydrogen gas is released in test tube 2 ,
Energy is released in the reaction involving hydrochloric acid and we can see in test tube 2 the reaction is going on
therefore option C i.e. The substances in both test tubes are reactive only at high temperatures. is the only statement which is NOT supported by the student's observation.
To know more about the chemical reaction between Magnesium and Hydrogen and this test.
brainly.com/question/19062002
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Answer:
Option D) Compound B may have a lower molecular weight.
Explanation:
Compound A and B are standing at the same temperature yet compound A is evaporating more slowly than compound B.
This simply indicates that compound B have a lower molecular weight than compound A.
This can further be seen when gasoline and kerosene are placed under same temperature. The gasoline will evaporate faster than kerosene because the molecular weight of the gasoline is low when compared to that of the kerosene.