Answer : The retention time is, 20 min
Explanation :
Retention time : It is defined as the amount of time a compound spends on the column after it has been injected.
Formula of retention time is:

Given:
Distance from injection point to center of peaks = 10 cm
Chart recorded speed = 0.5 cm/min
Now put all the given values in the above formula, we get:

Retention time = 20 min
Thus, the retention time is, 20 min
Answer:
trigonal planar
Explanation:
Tri=three, three-dimensional arrangement of the atoms that constitute a molecule.
Answer is: mass of 1,58 mol of water is 28,44 grams.
n(H₂O) = 1,58 mol.
M(H₂O) = 2 · 2 g/mol + 16 g/mol.
M(H₂O) = 18 g/mol.
m(H₂O) = n(H₂O) · M(H₂O).
m(H₂O) = 1,58 mol · 18 g/mol.
m(H₂O) = 28,44 g.
n - amount of substance.
M - molar mass.