Is the atom indicated with an arrow nucleophilic, electrophilic, acidic, more than one of these choices, or none of these choices? (For purposes of this question, acidic is defined as pKa ≤ 25.)Select all that apply. a) nucleophilicb) electrophilicc) acidicd) none of the above

c) acidic

Explanation:

pKa is a value which describes the acidity of a solution. The solution is pKa ≤ 25 which means that the solution is more acidic. The lower value of pKa tells us that the solution is more acidic but when the pKa value of solution increases the acidity of the solution is also decreases. Due to lower value of pKa, the acid in the solution is fully dissociates in water.-5 to 50 is the range of the value of pKa for different solutions.

a) the particles of the chair are strongly held together.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).