
⭐ Elements in which the last electron enters any one of the five d-oribitals of their respective penultimate shells are called as <u>d-block</u><u> </u><u>elem</u><u>ents</u> .
⭐ But the last electron of Zn , Cd , Hg and Cn enters in the s-oribital of their respective ultimate shells rather than the d-oribitals of their respective penultimate shells . Therefore, these elements cannot be regarded as d-block elements .
☃️ But properties of these elements resemble to the d-block elements rather than s-block elements .
☃️ Therefore, to make the study of periodic classification of elements more rational, they are studied along with d-block elements .
✍️ Thus <u>on the basis of properties</u> all transition elements are d- block elements, but <u>on the basis of electronic configuration</u> all d -block elements are not transition elements .
Correct answer: Option D, <span>
K = 5.04 × 10^52</span>
Reason:
We know that,
Ecell =

,
where n = number of electrons = 2 (in present case)
K = equilibrium constant.
Also, Ecell = <span>+1.56 v
Therefore, 1.56 = </span>

Therefore, log (K) = 52.703
Therefore, K = 5.04 X 10^52
<h3>
Answer:</h3>
Single displacement reaction
<h3>
Explanation:</h3>
- Single replacement reaction is a type of reaction in which a reactive element displaces a less reactive element from its compound.
- The reaction given above; Al + H₂SO₄ → Al₂(SO₄)₃ + H₂ is a single replacement reaction.
- This is because Aluminium takes the place of hydrogen atoms in sulfuric acid to form aluminium sulfate and hydrogen gas.
- Double replacement reaction is where cations or anions are exchanged between two compounds to form new compounds.
- For example the reaction; NaCl(aq) + AgNO₃(aq) → NaNO₃(aq) + AgCl(aq) is a double displacement reaction.
Answer: hydroxide ions
Explanation:
According to the Arrhenius concept, an acid is a substance that ionizes in the water to give hydronium ion or hydrogen ion and a bases is a substance that ionizes in the water to give hydroxide ion .
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
As KOH can give hydroxide ions on dissociation , it is considered as arrhenius base.

Answer: The beginning stage you decide to depict the area, or position, of an object.
Explanation: starting point or position