3. At the beginning of a titration to standardize the NaOH solution, Student A adjusted very carefully the initial burette volume to 0.00 mL, but he did not notice an important air bubble in the tip of the burette. At the end of the titration, the air bubble is gone. Explain the effect of that mistake on the calculated molarity MB. (Will the experimental MB calculated by Student A be higher or lower than the true MB value

The molarity of the solution will be higher.

Explanation:

Standarization is a process in which the molarity of the solution is made to be known. The concentration determined is exact by this process.

To standarize the solution of NaOH, first the acid used for titration is taken in a flask say 10 ml, indicator and water (in this case 50 ml). Then biuret is filled with NaOH of known molarity and initial volume is noted.

The air bubble not taken notice of in this case will lower the volume as molarity is inversely proportional to volume. When volume decreases molarity increases and vice-versa.

Formula used is

molarity =

The bubble will be formed with minimum volume thus volume is also lowered.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.