Electronegativity is the property of the element to attract electrons to its nucleus. The trend of electronegativity in the periodic table is decreasing from right to left and decreasing from top to bottom. hence from the given elements, the element with the highest electronegativity should be A.beryllium
Explanation:
As per Brønsted-Lowry concept of acids and bases, chemical species which donate proton are called Brønsted-Lowry acids.
The chemical species which accept proton are called Brønsted-Lowry base.
(a) 
is Bronsted lowry acid and
is its conjugate base.
is Bronsted lowry base and
is its conjugate acid.
(b)

is Bronsted lowry base and HCN is its conjugate acid.
is Bronsted lowry acid and
is its conjugate base.
(c)

is Bronsted lowry acid and
is its conjugate base.
Cl^- is Bronsted lowry base and HCl is its conjugate acid.
(d)

is Bronsted lowry acid and
is its conjugate base.
OH^- is Bronsted lowry base and
is its conjugate acid.
(e)

is Bronsted lowry base and OH- is its conjugate acid.
is Bronsted lowry acid and OH- is its conjugate base.
The answer to this is 22, confirmed by gradpoint
Answer:
9 moles of ions
Explanation:
Our compound is: CaCl₂(s)
We dissociate it:
CaCl₂(aq) → Ca²⁺ (aq) + 2Cl⁻(aq)
Per 1 mol of chloride, we have 1 mol of calcium cation and 2moles of chlorides, so in total we have 3 moles of ions.
Therefore in 3 moles of chloride, we would have 9 moles of ions (3 . 3)
Answer: Friction is a force that resists relative motion between two surfaces in contact. Depending on the application, friction may be desirable or undesirable.