Answer: I believe the correct answer would be A.
Answer: 4.21×10⁻⁸
Explanation:
1) Assume a general equation for the ionization of the weak acid:
Let HA be the weak acid, then the ionization equation is:
HA ⇄ H⁺ + A⁻
2) Then, the expression for the ionization constant is:
Ka = [H⁺][A⁻] / [HA]
There, [H⁺] = [A⁻], and [HA] = 0.150 M (data given)
3) So, you need to determine [H⁺] which you do from the pH.
By definition, pH = - log [H⁺]
And from the data given pH = 4.1
⇒ 4.10 = - log [H⁺] ⇒ [H⁺] = antilog (- 4.10) = 7.94×10⁻⁵
4) Now you have all the values to calculate the expression for Ka:
ka = 7.94×10⁻⁵ × 7.94×10⁻⁵ / 0.150 = 4.21×10⁻⁸
Atomic Mass will be 23 the new magnesium formed will be its isotope of magnesium.
We know that,
In stable condition
Number of electrons = Number of protons
Atomic number represents number of proton .
So, here number of proton is 12
Therefore, number of electron is 12
We know that -
Atomic mass = number of protons +Number of neutron
So if magnesium loses one neutron i.e. new number of neutron is 11
then its atomic mass changes.
New atomic mass will be
Atomic mass = 
Atomic mass = 23
This new element with atomic mass 23 and atomic number 12 is the isotope of magnesium.
To know more about isotopes
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Answer : The correct options are,
and 
Explanation :
Single displacement reaction : It is a type of chemical reaction in which the more reactive element displaces the less reactive element.
Option A reaction : 
It is an example of double displacement reaction because in this reaction a positive cation and a negative anion of the two reactants exchange their places to form two new products.
Option B reaction : 
It is an example of single displacement reaction.
Option C reaction : 
It is an example of combination reaction because in this reaction two reactants react to give a single product.
Option D reaction : 
It is an example of decomposition reaction because in this reaction a single reactant decomposes into two or more products.
Option E reaction : 
It is an example of single displacement reaction because in this reaction the most react element, aluminium displaces the less reactive element, hydrogen.
Hence, the options B and E are single displacement reactions.
Answer is: hydrogen bonding.
Methanol has stronger intermolecular bonds than methane.
Intermolecular forces are the forces between molecules or particles.
There are several types of intermolecular forces: hydrogen bonding, ion-induced dipole forces, ion-dipole forces andvan der Waals forces.
Hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (H), covalently bound to a highly electronegative atom such as flourine (F), oxygen (O) and nitrogen (N) atoms.