What is KOH ?

All of you know that, Potassium hydroxide (KOH) is a strong base which is generally used in chemical reactions.KOH is highly corrosive base and also the caustic chemical.

Chemicals or Apparatus used for preparation 0.1 N KOH solution :

Chemicals:

• KOH powder (5.611g)

• Distilled water ( 1L or 1000 ml)

Apparatus:

• Weighing paper

• Volumetric flask

• Pipette

• Glass rod

How can you prepare a 0.1 N KOH solution?

For preparing 0.1 N KOH solution, we need to follow below steps:

Step 1) Calculate the number of grams of KOH required:

Molar mass of KOH is 56.11 g/mol.

So, Grams of KOH required is given as:

Normality (N) × Equivalent weight × Volume(L)

For 0.1 N solution of KOH, the equivalent weight is 1 ( Because it is the molar mass divided by the number of hydrogen ions which can donate KOH molecule). Hence. The equivalent weight of KOH is same as the molecular weight of KOH that is 56.11 g/mol.

Puts this all values in the above formula, we get:

Grams of KOH = 0.1N × 56.11g/mol × 1L

Grams of KOH needed = 5.611 g

So, we need 5.611 g of KOH.

Step 2) Weighing out the required amount of KOH:

Measures the amount of KOH by using balance to accurate at least 0.001 g.

Weighing KOH powder by using weighing paper or weighing boat.

Step 3) Dilute the solution with amount of water:

Take 1L or 1000 ml distilled water. Take a clean and dry volumetric flask. Firstly, add little amount of distilled water to the volumetric flask. Then add the KOH powder to the volumetric flask. Add it slowly and stir the solution with glass rod until it is completely dissolved.

Step 4) Transfer the amount of KOH solution in volumetric flask :

When KOH totally or completely soluble then add the distilled water to the volumetric flask up to the mark 1000ml or 1L. You can check the volume of the solution by reading meniscus at eye level.

If volume of solution is less then add more water. And if volume is higher than 1000 ml then removing some of the solution with a pipette until the bottom of the meniscus is exactly at the reading 1 L.

The 0.1 N KOH solution is now use for chemical applications.

Step 5) Store and Label the solution:

this 0.1 N KOH solution in clean and dry container. Don't forget to seal and label the container with date and concentration.

Precautions that should be taken during preparing 0.1 N KOH solution:

1. Always wear apron and goggles.

2. Always add KOH to water, because reaction between water and KOH is exothermic that can cause the solution to boil and splatter which is very harmful.

3. For stirring the solution use glass rod or magnetic stir bar. Don't use plastic/ metal rod.

4. For handling KOH wear protective apparatus like gloves, lab coat etc.

5. KOH handled carefully because it can reacts with acids, metals, and other organic compounds.