Summary of Solution Preparation and Concentration Calculations

Preparation of Solutions

  • 10% NaCl Solution Preparation

    • Volume: 200 ml
    • Concentration: 10% (w/v)
    • Source Solution: 35% (w/v) NaCl
    • Calculation:
      C<em>1=35%C</em>2=10%V2=200 mlC<em>1 = 35\% \quad C</em>2 = 10\% \quad V_2 = 200 \text{ ml}
    • Use dilution formula: C<em>1V</em>1=C<em>2V</em>2C<em>1V</em>1 = C<em>2V</em>2
    • Rearranging: V<em>1=C</em>2V<em>2C</em>1V<em>1 = \frac{C</em>2 V<em>2}{C</em>1}
    • Final calculation for $V_1$.

  • Acetic Acid (HAC) Preparation

    • Volume: 300 ml

    • Concentration: 0.24 mol/dm³

    • (i) From 100% (w/w) HAC

    • Molecular Weight: Calculate using C, H, O.

    • Use: C=nVC = \frac{n}{V}, where $n$ = moles.

    • (ii) From 85% (w/w) HAC

    • Relative Density: 1.06 g/cm³

    • Use density to find mass: Volume×DensityVolume\times Density

    • Convert percentage to molarity using molecular weight.

Concentration Calculation for Na₂HPO₄ Solution

  • Mass in Solution: 15 g

  • Total Volume: 250 ml (0.25 dm³)

  • (a) g/l Calculation:

    • C(g/l)=mass(grams)volume(dm3)C(g/l) = \frac{mass(grams)}{volume(d\text{m}^3)}
    • Calculation: C(g/l)=15 g0.25 dm3=60g/lC(g/l) = \frac{15 \text{ g}}{0.25 \text{ dm}^3} = 60 g/l

  • (b) % (w/v) Calculation:

    • \text{% (w/v)} = \frac{mass(grams)}{volume(ml)} \times 100
    • Calculation: C(%)=15 g250 ml×100=6C(\%) = \frac{15\text{ g}}{250\text{ ml}} \times 100 = 6%

  • (c) Molarity (M) Calculation:

    • Molar Mass of Na₂HPO₄: Calculate.
    • Molarity: M=nVM = \frac{n}{V}
    • Calculation: C(M)=C(g/l)molar mass (g/mol)C(M) = \frac{C(g/l)}{molar \, mass \, (g/mol)}

  • (d) Ionic Strength Calculation:

    • Formula: I=12ΣC<em>iZ</em>i2I = \frac{1}{2} \Sigma C<em>i Z</em>i^2
    • Here, $Ci$ = concentration of each ion (in mol/dm³), $Zi$ = charge of the ion.