The water hardness is meant a measure of the total concentration of calcium and magnesium ions. Actually, the sum of all polyvalent metal ions, which are capable of replacing sodium

and potassium in soap and form sparingly soluble compounds, are important for water hardness, but calcium and magnesium predominate. Here we use the German designation $dH,$

where $1dH$ means that the water has a concentration of $Ca+Mg$ corresponding to $10mg$ of CaO per litre $($ MwCaO$=56\mathrm{.}0774\frac{g}{m}ol)$ Below $6dH$ is counted as soft water and over $6$

medium and hard. Calcium and magnesium can be determined together by complexometric titration with EDTA at pH $10.$ The end point is indicated by an indicator called Eriochrome black

T$.$ The analytical procedure was: "EDTA solution was weighting $0\mathrm{.}7130g$ of $Na-$EDTA transferred to a $1000mL$ volumetric flask and diluted to the mark with distillated water $($Mw Na$-$EDTA $=$

$372\mathrm{.}24\frac{g}{m}ol).$ Then, $25mL$ water sample from a tap water was taken out by pipette and $5mL$ buffer $pH10$ was added, and a few drops of indicator. Finally, the sample was titrated using a

burette filled with EDTA solution until a color change from purple to blue. It was delivered $11\mathrm{.}40mL"$ Use the following information provided by the supplier. Volumetric flask: $V=(1000+-0\mathrm{.}5)$

$mL($tolerance from supplier's catalogue$).$ Pipette: The pipette had previously been calibrated by repeating portions of distillated water weighed, which converted gave the following

volumes: $24\mathrm{.}78$;$24\mathrm{.}82$;$24\mathrm{.}84mL$ at the current temperature. Burette: $+-0\mathrm{.}05mL$ tolerance from supplier's catalogue. Consider one$-$time error during the drainage of the burette. Balance:

$u(M)=0\mathrm{.}0001g.u(MwCaO)=0\mathrm{.}0017\frac{g}{m}ol$ and $u(MwNa-$EDTA$)=0\mathrm{.}01\frac{g}{m}ol$

Questions: a$)$ What is the degree of hardness expressed as $dH?$

b$)$ What is the expanded uncertainty with $95\%$ confidence for $dH?$

c$)$ Which parameters have the greatest impact and the second largest impact on overall uncertainty? For this task, you need to calculate the index numbers using the Eq$2.$ Express all of

them in $\%.$

$*$Note$,$ it is highly recommendable to use Excel$/$Matlab$,$ and please harmonize the units to obtain reliable results of $dH$ in the range of $4$ to $6.$

The following must be properly included. $*$ Model, equations, and uncertainty estimation. $*$ The value of the hardness of water and the expanded uncertainty must be correct. $*$ All

parameters must be defined and have the right unit. Indicate the distributions for each uncertainty. No figures should be included for the model equation. Unit conversion is done with the

constants defined. $*$ Questions in the text must be correctly addressed $(a,b$ and $c.$Hello, I need a lot of help with this task. It feels very comprehensive to me$.$ I have exams coming up and don't have much time to delve deeper into this than I already have. Could someone please do it for me with step$-$by$-$step detailed and clear calculations so that I can understand as well?