Using pH to determine [H+]
10^-pH= 10^-2.45 = 2.1 x 10^-3
<span>
Now,
Ka=[H=][A-]/[HA] </span>
<span>So,
(2.1 x 10^-3)^2/0.0136 - (2.1 x 10^-3) </span>
<span>Ka=2.5 x 10^4</span>
Answer:
- Take a cup of water, as solvent, in a kettle and heat it.
- Add sugar, the solute, to water. Heat it. The sugar dissolves in water.
- Sugar is soluble in water
- Add some tea leaves. It is insoluble in
- water. Colour of tea leaves goes into the solution.
- Boil the content and add milk, which is soluble in water.
- Filter the tea with the help of a strainer. The tea collected in the cup is a filtrate.
- The tea leaves collected on the strainer is residue.
<u>-TheUnknownScientist 72</u>
Answer:
a) Y³⁺ > Eu²⁺ > Fr⁺ > Sr²⁺
b) Sr > Fr > Eu > Y
Explanation:
Y is the least reactive metal because it does not react with any of the other solutions.
Sr is the most reactive metal because it reacts with all of the other solutions.
Sr + 2Fr⁺ ⟶Sr²⁺ + 2Fr
3Sr + 2Y³⁺ ⟶ 2Sr²⁺ + 2Y
Sr + Eu²⁺ ⟶ Sr²⁺ + Eu
Fr is more reactive than Eu because it reacts with Eu(NO₃)₂.
2Fr + Eu²⁺ ⟶ 2Fr⁺ + Eu
The order of reactivity is
Sr > Fr > Eu > Y
b) Reducing agents
In each of the above reactions. the more reactive metal is acting as a reducing agent — it is donating electrons to the cation of the other metal.
Thus, the order of activity of reducing agents is
Sr > Fr > Eu > Y
a) Oxidizing agents
The metal cations are the oxidizing agents.
The order of reactivity of the oxidizing agents is the reverse order of the reducing agents
Y³⁺ > Eu²⁺ > Fr⁺ > Sr²⁺
c) Standard reduction potential table
See the image below.
Answer:
493 mL has to evaporate
Explanation:
Step 1: Data given
Initial volume of the sodium chloride (NaCl) solution = 750 mL = 0.750 L
Molarity of the sodium chloride (NaCl) solution = 1.2 M
The concentration needed = 3.5 M
Step 2: Calculate the volume needed
To have a higher concentration we should lower the volume
C1*V1 = C2*V2
⇒C1 = the original concentration = 1.2 M
⇒V1 = the initial volume = 0.750 L
⇒C2 = the new concentration = 3.5 M
⇒V2 = the new volume needed = TO BE DETERMINED
1.2 M * 0.750 L = 3.5 M * V2
V2 = 0.257 L
To have a concentration of 3.5 M we need 0.257 L or 257 mL
Step 3: Calculate the volume of water to evaporate
750 mL - 257 = 493
493 mL has to evaporate