To determine the concentration of a solution of chlorous acid, a 50.00-mL sample is placed in a flask and titrated with a 0.1382 M solution of sodium hydroxide. A volume of 26.37 mL is required to reach the phenolphthalein endpoint. Calculate the concentration of chlorous acid in the original sample.

The answer to your question is Molarity = 0.073

Explanation:

Data

Chlorous acid = HClO₂

Volume = 50 ml

[HClO₂] = ?

Sodium hydroxide = NaOH

[NaOH] = 0.1382 M

Volume = 26.37 ml

Process

1.- Write the balanced chemical reaction

                   HClO₂  +  NaOH  ⇒   H₂O + NaClO₂

2.- Calculate the moles of NaOH

Molarity = moles / volume

Moles = Molarity x volume

Moles = 0.1382 x 0.02637

Moles = 0.00364

3.- Calculate the moles of HClO₂

                 1 mol of HClO₂ 1 mol of NaOH

                 x                         0.00364 moles

                 x = (0.00364 x 1) / 1

                 x = 0.00364 moles of HClO₂

4.- Calculate the concentration of HClO₂

Molarity = 0.00364 / 0.05

Molarity = 0.073                  

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

explanation: