Caustic embrittlement, Chemistry

Assignment Help:

Caustic Embrittlement: Caustic embrittlement is a type of boiler corrosion caused by using highly alkaline water in the boiler. During softening process by lime-soda processes, free Na2CO3 is usually present in small proportion in the softening of water. In high pressure boilers, Na2CO3 decomposes to give sodium hydroxide and carbon-dioxide.

  Na2CO3 + H2O = 2NaOH + CO2

And this makes boiler water "Caustic". The NaOH containing water flows into the minute hair cracks, always present in the inner side of boiler, by capillary action. Here water evaporated and the dissolved caustic soda concentration increases progressively. This caustic soda attacks the surrounding area, thereby dissolving iron of boiler as sodium ferrate. This causes embrittlement of boiler parts, causing even failure of the boiler. Caustic cracking can be explained by considering the following concentration cell. The iron surrounded by the dilute NaOH becomes the cathodes sides, which the iron in contact with concentrated NaOH becomes anodic part, which is consequently dissolved or corroded.

 

 


Related Discussions:- Caustic embrittlement

Potentiometry, principle and application of potentiometry in biochemistry

principle and application of potentiometry in biochemistry

Preparation of cyclohexanol from cyclohexene, 1)why hydroboration leads to ...

1)why hydroboration leads to anti-markovnikov addition of hydrogen whereas most electrophilic additions to alkenes result in Markovnikov addition. 2) draw the full mechanism and id

The positive charge of an atom, The positive charge of an atom is: (1) ...

The positive charge of an atom is: (1) Spread all over the atom    (2) Distributed around the nucleus  (3)Concentrated at the nucleus (4) All of these Ans: Concentr

Determine discharge coefficient, The determination of k is not a strait for...

The determination of k is not a strait forward exercise. Model it from first principles using Bernoulli's equation would produce a square root relationship and would probably have

Freezing and Boiling points, Calculate the molarmass of a nonelectrolyte th...

Calculate the molarmass of a nonelectrolyte that lowers the freezing point of 25.00g of water to -3.9 degrees C when 4.27 g of the substance is dissolved in the water.

Show the chemical properties of aluminium, Q. Show the chemical properties ...

Q. Show the chemical properties of Aluminium? Aluminium has a very high affinity for oxygen; this is reflected in high exothermic heat of formation of Al 2 0 3 (-1676 kJ mol -

Nucleic acids - biomolecules, Nucleic Acids - Biomolecules  In every li...

Nucleic Acids - Biomolecules  In every living molecule there are available in nucleo-proteins that are made up of proteins and natural polymers of great biological significance

Hydrogen and its compounds, A sample of water contains: suspended matter = ...

A sample of water contains: suspended matter = 100 mg; Ca(NO3)2 = 16.4 mg/L; MgSO4 = 24 mg/L; MgCl2 = 19 mg/L; NaOH = 40 mg/L and KOH = 56 mg/L. Calculate temporary, permanent and

Laws of chemical combination, how many grams of silicon are present in 35 g...

how many grams of silicon are present in 35 grams of silicon?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd