Answer:
0.23
Explanation:
- It is known that, the mass to mass ratio of the salt to water
= (mass of salt / mass of water)
= (25.0 g / 105.0 g)
= 0.23
As mentioned above, phosphoric acid has 3 pKa values, and after 3 ionization it gives 3 types of ions at different pKa values:
H₃PO₄(aq)
+ H₂O(l) ⇌ H₃O⁺(aq) + H₂PO₄⁻ (aq) pKₐ₁
<span>
</span>H₂PO₄⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + HPO₄²⁻ (aq) pKₐ₂
HPO₄²⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + PO₄³⁻ (aq) pKₐ₃
At the highest pKa value (12.4) of phosphoric acid, the last OH group will lose its hydrogen. On the picture I attached, it is shown required protonated form of phosphoric acid before reaction whose pKa value is 12.4.
Answer:
Option (2)
Explanation:
Cohesion is usually defined as the contrasting property by which the water molecules are attached to one another, and adhesion is the property by which the molecular substances are linked to the molecules of other substances.
Since, the water molecules are able to form inter-molecular hydrogen bonding, so they are comprised of strong cohesive force.
And, as the water molecules are able to stick to the walls of the container, so they tend to show more of the properties for adhesion.
Thus, according to the given condition, water molecules are sticking to other substances and this is the property of adhesion.
Hence, the correct answer is option (2).
A bicycle rusting after it is left in the rain is an example of a chemical reaction because it involves oxidation (Option d).
<h3>What is a chemical reaction?</h3>
A chemical reaction can be defined as a phenomenon in which one or more substances called reactants react to form one or more different compounds, which are known as products.
A chemical reaction may include an enzyme that works to increase the seed of the reaction in normal conditions by lowering the activation energy of the reaction.
Therefore, we can conclude that a chemical reaction such as oxidation in a bicycle is a process where reactants combine or break down to form the products of such reaction.
Complete question:
Which of the following situations contains an example of a chemical reaction?
a. Ice forming after water is placed in a freezer
b. Watercolor paint drying on paper
c. a sugar cube dissolving in a glass of water
d. a bicycle rusting after it is left in the rain
Learn more about chemical reactions here:
brainly.com/question/11231920
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Today scientist don't believe there's life in this solar system but there is proof of living things that once used to live on mars. there might be life in our universe and other galaxies.
Explanation: