Skip to main content

p Alkalinity and m Alkalinity

What is p Alkalinity?
  • The  term  p  Alkalinity  stands  for  “Phenolphthalein  –  Alkalinity”. 
  •  It  is  the  measurement  of Hydroxide and carbonate ion amount. 
  • It is determined by titrating a water sample with an acid of a known concentration in the presence of phenolphthalein as the indicator.
 What is m Alkalinity?
  • The  total  measurement  of  Hydroxide  bicarbonate  and  carbonate  ions amount is given by m Alkalinity. The letter m refers to Methyl orange.
  • It is the indicator that is used to determine the total alkalinity given by the above hydroxide and carbonate species.
  • When methyl orange is added, it gives its color change only  in its pH range which is, 3.1  –  4.4. Since only  trace  concentrations  of  other  acids  are  dissolved  in  water  except  for  carbonic  acid,  m Alkalinity can be considered as the total alkalinity because it gives the total carbonate alkalinity.
What is the difference between p Alkalinity and m Alkalinity?

p Alkalinity vs m Alkalinity
  • p alkalinity is the measurement of alkalinity given by hydroxide ions and half of the carbonate alkalinity.
  • m alkalinity is the measurement of alkalinity given by hydroxide ions and total carbonate alkalinity.
Indicator
  • Phenolphthalein indicator is used to determine p alkalinity.
  • Methyl orange is used to determine m alkalinity.
pH Range
  • p alkalinity is measured at a range of 8.3 –10.0 pH.
  • m alkalinity is measured at a pH range of 3.1 – 4.4.

Comments

Popular posts from this blog

Why is a man hole door elliptical in shape?

Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole  is lesser in size than the corresponding circular hole. More over it is prime concern to have a  smoothed generous radius at the corners to eliminate stress concentration. Hence other  geometrical shapes like rectangle and square are ruled out.  To compensate for the loss of material in the shell due to opening, a doubler ring has to be  provided around the opening. The thickness of the ring depends on the axis length along the  dirrection in which the stresses are maximum and the thickness of the shell. It is important to  align the minor axis along the length of the vessel, as the stress in this direction is  maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t=  thickness of the shell plating  Circumferential stress: Pd/4t  More over a considerable material and weight saving is achieved as minor is along the  direction of maximum stress.

Shell Expansion Plan

It is a two dimensional drawing of a three dimensional surface of the ship’s hull form. This plan is very useful for the following information:It is used for marking the location of a hull Damage on this plan by identifying the strake number , letter and frame number so that the exact location of the damage and also suggested repairs are marked in a localised copy. The shell expansion can be used for finding areas of painting surfaces such as topside, boot topping and bottom areas by applying Simpsons rules directly.  In the shell expansion the vertical scale used is different from the horizontal scale and a suitable adjustment has to be made when calculating areas. This becomes useful in solving disputes concerning areas of preparation and painting. It gives information on the thickness of the original strake which is indicated by the number in the circle shown in the strake.  The quality of steel used is also shown by letters A,B,D E and AH, BH,DH, EH.