Units of hardness and their relationship, Chemistry

Q. Write short note on units of hardness and their relationship.

Sol. Units of hardness and their relationship.

(1)         Parts Per million (ppm): It is defined as the number of parts by weight of CaCO3 equivalent present in per million (106) parts by weight of water.

1 ppm = 1 part of CaCO3 equivalent hardness in (106) parts of water.

(2)         Milligrams per litre (mg/l): It is defined as the number of milligrams of CaCO3 equivalent hardness present in one litre of water.

1 mg/L = 1 mg of CaCO3 equivalent hardness present per litre of water.

It can be easily proved that 1mg/L = 1 ppm, for water

Weight of 1 litre of water = 1kg = 103g = 106mg

= 1000*1000g= 106mg

1mg/L = 1mg of CaCO3 equivalent hardness per 106 parts of water.

         1mg/L = 1 part of CaCO3 equivalent hardness per 106 parts of water.

1mg/L = 1ppm

(3)         Degree Clark (0Cl): It is defined as the parts of CaCO3 equivalent hardness per 70,000 parts of water or it is number of grains (1/7000lb) of CaCo3 equivalent hardness per gallon (10lb or 70,000 grains) of water. 10 Clark= 1 part of CaCo3 per 70,000 part of water.

(4)         Degree of French (0Fr): It is defined as the parts of CaCO3 equivalent hardness per Lac (100000) parts of water.

10Fr = 1 part of CaCO3 equivalent hardness per (105) parts of water.

(5)         Milli equivalent per litre (meq/L): It is defined as the number of milli equivalents of hardness present per litre.

1 meq/L = 1 meq of CaCO3 per L of water

                 = 10-3 * 50g of CaCO3 eq. per litre of water

                   =   10-3 * 1000 * 50 mg of CaCO3 eq. per litre of water

                 = 50mg of CaCO3 eq. per litre of water

                 = 50mg/L of CaCO3 eq. per litre of water = 50 ppm

                 = 50mg of CaCO3 eq. per 106 litre of water

                 = 1 mg of CaCO3 eq. per 106 /5 mg litre of water

                  = 1 part of CaCO3 equivalent per 20,000 parts of water.

Relationship between different units of hardness:

1 ppm = 1 part per 1000000 parts of water

1 0Fr = 1 part per 100000 parts of water

1 0Cl = 1 part per 70000 parts of water

1 mg/L = 1 part per 1000000 parts of water

1 meq/L = 1 part per 20000 parts of water

Hence: 1000000 ppm = 1000000Fr = 700000Cl = 1000000 mg/L = 20000meq/L

= 100 ppm = 100Fr = 70Cl = 100mg/L = 2 meq/L

    1 mg/L     = 1 ppm = 0.10Fr = 0.070Cl = 0.02 meq/L

10Cl = 14.3 ppm = 1.433 0Fr = 14.3 mg/L = 0.286 meq/L

10Fr = 10 ppm = 10 mg/L = 0.7 0Cl = 0.2 meq/L

1 meq/L = 50 mg/L = 50 ppm = 5 0Fr = 0.35 0Cl

Posted Date: 7/21/2012 7:04:25 AM | Location : United States







Related Discussions:- Units of hardness and their relationship, Assignment Help, Ask Question on Units of hardness and their relationship, Get Answer, Expert's Help, Units of hardness and their relationship Discussions

Write discussion on Units of hardness and their relationship
Your posts are moderated
Related Questions
Q. What is an Emulsifier? An emulsifier is a compound that contains both polar and nonpolar groups and thus is drawn to the interface between the two phases of an emulsion to


DNA nucleotides Adenine + Deoxy ribose sugar + Phosphate → Adenosine phosphate Guanine


why is filtration in soil and water a slow process and explain the colour change in the filtrate

If 0.5 mol of BaCl 2 is mixed with 0.20 mol of Na 3 PO 4 , the maximum amount of Ba 3 (PO4) 2 that can be formed is 3 BaCl 2 + 2 Na3PO 4 = Ba 3 (PO4) 2 + 6NaCl Here cle

If electron falls from n=3  to n= 2 , then emitted energy is: (1) 10.2ev                            (2) 12.09 ev           (3) 1.9ev                              (4)0

#how do i know the factor of a compound when getting its equivalent weight?

primary and secondary nitro compounds chemical test..

Sir any method to learn the arrangement of functional group in poly functional compound ????