Question: In some places a hard, cement concrete structure with pores is desired. The concrete pores can be ma...

Question

In some places a hard, cement concrete structure with pores is desired. The concrete pores can be made by the release of oxygen gas from inside the concrete by:
(A) Steam
(B) Hydrogen peroxide
(C) Sodium peroxide
(D) Ozone

Answer 1

Solution

Hint : To answer this question we will first talk about carbonation in cement industries, the way they are made using carbon dioxide, carbonic acid, etc. after discussing in detail we will answer the question and state other uses of the compound as well.

Complete Step By Step Answer:
First let us talk about a process called carbonation:
Carbonic acid ( $H_2CO_3$ ) is generated when ambient carbon dioxide ( $CO_2$ ) dissolves in the cement pore solution. The concrete pore solution's pH is subsequently reduced, and some of the alkaline solid phases are neutralized. Calcium hydroxide ( $Ca(OH)_2$ ), for example, will be transformed to calcium carbonate ( $CaCO_3$ ).
As the alkaline solid phases' reserves are spent, a low-pH zone (the carbonated zone) stretches from the surface through concrete. Carbonation is the word for this process. Carbonation normally increases the concrete's strength by a little amount. A drop in pH below 10 at the steel, on the other hand, may make the steel passive film thermodynamically unstable.
In all these processes, Hydrogen peroxide is used to release oxygen gas to make concrete pores.
Hence the correct answer is option B.

Additional Information:
Chemical pulp, mechanical pulp, and recycled pulp are bleached with industrial hydrogen peroxide (de-inking). Because it is the only chemical required, the use of commercial hydrogen peroxide in pulp and paper bleaching raises brightness levels, improves brightness stability, and lowers manufacturing costs.

Note :
Do not think that the only function of hydrogen peroxide in cement industries is to release oxygen. It acts as a bleaching agent too. To help bleach out part of the pigment from the concrete pours, oxalic acid or hydrogen peroxide is used. Graffiti can also be removed with sodium hydroxide, xylene, or methyl ethyl ketone solutions.