DETERMINATION OF HARDNESS IN WATER FROM SELECTED WELLS, RIVER AND RAIN WATER IN NASARAWA USING COMPLEXOMETRIC TITRATION

DETERMINATION OF HARDNESS IN WATER FROM SELECTED WELLS, RIVER AND RAIN WATER IN NASARAWA USING COMPLEXOMETRIC TITRATION

ABSTRACT

Water (H₂O) is the most abundant liquid substances on the earth crust, the presence of dissolved salt of calcium and magnesium in the natural water makes water to be hard (hardness in water), though this may not have effect on human and animal, but should be controlled for effective material and object usage.  This project work revealed total hardness in Nasarawa water, with ordinary river water contained 82mg/litre and the heat river water contained 61.0mg/litre.  (the highest) ordinary rain water, 64mg/litre and heat rain water, 44.0/litre and ordinary well water which contained, 48mg/litre and heat well water 26.0mg/litre (the lowest hard water) by using the complexometric titration method.

CHAPTER ONE

1.0 INTRODUCTION

Water (H₂O) is the only liquid substance to be found on earth in significant amounts.  Water as a liquid is also reality under conditions on earth to be solid and gaseous form.  Almost all the activities in life constitute use of water.  All the systems in living things make use of about 70% water for their normal functioning.  Infact, it is difficult to think of life without water (Ababio, 2003).

Water is one of the most common substances known.  It is a good solvent for many substances (Universal Solvent) and rarely occurs in its pure form in nature (Ababio 2003).  As a result of the solvent properties of water, the naturally occurring liquids (water) always contains some dissolved materials, particularly ionicsubstances.  The presence of metal ions, such as calcium ion (Ca²⁺) and magnesium ion (mg ²⁺) in natural water causes, hardness in water (Ababio, 2003).  Water is said to be hard when it does not from lather readily with soap or toothpaste (Ababio, 2003), the metal ions calcium and magnesium (Ca²⁺ and mg ²⁺) in the natural water will react with soap (sodium salt of steric acid and similar organic acids) to produce a curly precipitate of calcium and magnesium salts (Ababio, 2003).

Thus, the hardness of water can be removed by a process of water softening. (Ababio, 2003).  The hardness of water can be temporary hardness or permanent hardness depending on the presence of dissolved salt compound in the natural water (Ababio, 2003).  Some presence of water softening are: boiling the hard water, ion-exchange resin (sodium zeolite), addition of washing soda (Na₂CO₃), addition of Caustic soda (NaOH) and addition of slaked lime (CaCOH)² into the hard water to remove the calcium ion (Ca ²⁺) and magnesium ion (mg ²⁺) in the water (Ababio, 2003).

Complexometric titration is the type of wet titration which involves the combination of compound or ion. The quantity of hardness ion can be determined by complexometric or EDTA titration.  EDTA ethylene diame tetraacetic acid of disodium salt) will be used a tet its ionized from (Clescesi and Greenberg 2003).  It is able to form soluble compexies with calcium and magnesium (Ca²⁺ and mg ²⁺).  As EDTA is added to the water sample in minute quantity) and form mere stable complexes with calcium and magnesium (Clescesi and Greenberg, 2013).  The colour change from red to distinct blue is to be observed at the end point of the titration to obtain the volume of EDTA for the reaction (Clescesi and Greenberg, 2013).

The natural water sample in Nasarawa to be used are river water, well water and rain water.  This natural water contained different quantity of hardness (Ca²⁺ and mg²⁺) based on their constituent in nature.  River water contains a lot of dissolved air, mineral salt bacterial and organic remains (Clesecesi and Greenberg, 2013).

It should be specially purified before drinking.  Well water contains a lot of clay and other mineral salts, the water from the deep wells tend to be less polluted than from the surface wells.  It is safe to boil well water before drinking (Clescesi and Greenberg, 2013).  Rain water is the purest form of natural water, because it is formed as a result of the condensation of water vapour in the atmosphere (Ebbing and Gummon, 1999).

1.1     AIMS AND OBJECTIVES

This project is aimed at determination of the total hardness present in natural water (river, rain, and well).

The objectives include:

1. To determine the concentration of Ca²⁺ and Mg²⁺ in samples of water from river, rain and well in Nasarawa.
2. To compare the total hardness of the common sources of water in Nasarawa.

CHAPTER TWO

LITERATURE REVIEW

2.1     HARDNESS IN WATER

Hardness in water is defined as the present of multivalent cations, hardness in water can also be defined as water that does not produce lather with soap solutions or toothpaste, but produces white precipitate (Scum) (Shaper and Pocock, 2012).  Hardness is the water that has high mineral content (mainly calcium and magnesium ions).  Hardness mineral primarily consists of calcium (Ca²⁺) and magnesium (mg²⁺) metal cations, and sometimes other dissolved compounds such as bicarbonate (CaCHO₃)₂ and sulphate (CaSO₄ and mgSO₄).  Soap is the sodium or potassium salt of an organic acid.  It is usually sodium octadecanote or sodium serrates (C₁₇H₃₅COONa).  When soap is added to hard water, the dissolved salts in the water will immediately react with the soap molecular in the following ways: