Practical skills

Medium

A student plans a titration experiment to determine the concentration of a lithium hydroxide solution using dilute nitric acid.

The student writes their method.

A Add a few drops of phenolphthalein indicator.
B Fill the burette with dilute nitric acid. Record the initial reading on the burette.
C Empty the lithium hydroxide solution from the pipette into a conical flask.
D Stop adding the dilute nitric acid when the indicator just changes colour.
E Repeat these steps until you have two concordant results.
F Use a pipette filler to fill a glass pipette with 25.0 cm³ of lithium hydroxide solution.
G Add the dilute nitric acid to the lithium hydroxide solution while swirling the conical flask.

The steps in the method are not in the correct order.

Arrange the letters to show the correct order of the steps. The first and last steps have been filled in for you:

\text{B} \rightarrow \underline{\quad\quad} \rightarrow \underline{\quad\quad} \rightarrow \underline{\quad\quad} \rightarrow \underline{\quad\quad} \rightarrow \underline{\quad\quad} \rightarrow \text{E}

[2]

This is the equation for the reaction in the experiment:

\text{LiOH} + \text{HNO}_3 \rightarrow \text{LiNO}_3 + \text{H}_2\text{O}

[1]

Water is a waste product in this reaction.

Calculate the atom economy for the production of lithium nitrate ( $LiNO3\text{LiNO}_3$ ).

Relative atomic mass ( $A_r$ ): $H=1.0\text{H} = 1.0$ , $Li=7.0\text{Li} = 7.0$ , $N=14.0\text{N} = 14.0$ , $O=16.0\text{O} = 16.0$

[3]