The correct answer would be A
Explanation: I did the math
The absolute value of the difference in electronegativity (ΔEN) of two bonded atoms provides a rough measure of the polarity to be expected in the bond and, thus, the bond type. When the difference is very small or zero, the bond is covalent and nonpolar. When it is large, the bond is polar covalent or ionic.
The answer is b, because all of the other compounds are covelent
So there are basically five types of chemical reactions which have their general formulas.
They are:
1. Combination reaction
General formula : A+B = AB
2. Decomposition reaction
General formula: AB = A+B
3. Single displacement reaction
General formula: AB+C = CB + A
4. Double displacement reaction
General formula: AB+CD = CB+AD
5. Acid-base reaction
General formula: A+B = S+W
You should check and compare with examples.
NH3 +HCl ----> NH4Cl
moles of HCl used = (0.8 x 17.4) /1000= 0.0139 moles
by use of reacting ratio between HCl to NH4Cl which is 1:1 therefore the moles of NH4Cl is also = 0.0139 moles
molar concentration = moles /volume in liters
molar concentration is therefore= (0.0139/5) x1000 = 2.7 M