Preparation, properties and uses of baking soda - class-XI

Baking soda,$(NaHCO _3)$ also known as sodium bicarbonate, is widely used in baking. This is because it has leavening properties, meaning it causes dough to rise by producing carbon dioxide. Aside from cooking, baking soda has a variety of additional household uses and health benefits.

In Solvay process, sodium bicarbonate is precipitated due to common ion$(Na^+)$ effect provided by brine (concentrated NaCl Solution).

Baking soda is also known as sodium hydrogen carbonate.

The baking powder consists of sodium bicarbonate and calcium dihydrogen phosphate.In this process the ${ H } _{ 2 }{ PO } _{ 4 }$ acts as acid in the baking powder and then reacts with ${ NaHCO } _{ 3 }$  so that carbon dioxide that expands in the food items.When sufficient heat is given bond will breaks between  $Ca$ and ${ H } _{ 2 }{ PO } _{ 4 }$ and then reacts with 

Baking soda,which has chemical name sodium bicarbonate $(NaHCO _3)$ is slightly basic in nature.Which means it tastes bitter as acid taste sour and bases taste bitter.

Baking powders contains sodium bicarbonate and one or more acid salts. Usually 30% sodium bicarbonate, 5-12% monocalcium phosphate, and 21-26% sodium aluminium sulfate and starch.

Its chemical formula is $NaHCO _3$(sodium bicarbonate). Its formula consists of one sodium (Na) atom, one hydrogen (H) atom, one carbon (C) atom and three oxygen (O) atoms. It is commonly known as baking soda, bread soda, bicarbonate of soda, and cooking soda.

Milk of magnesia is an aqueous suspension of magnesium hydroxide $[Mg(OH) _2]$ used to treat acid indigestion.
Also sodium bicarbonate is used for antacid medicinal preparation.

Sodium bicarbonate is amphoteric, reacting with acids and bases. It reacts violently with acids, releasing CO2 gas as a reaction product. Because of $NaHCO _3$ is a weak base the pH value should be greater than 7.

RCOOH decomposes $NaHCO _3$ to liberate $CO _2 $ which comes from $NaHCO _3$.
$NaHCO _3 + RCOOH \rightarrow RCOONa + H _2O + CO _2$

${ NaHCO } _{ 3 }$ is sodium bicarbonate or known as sodium hydrogen carbonate. Sodium bicarbonate is a white solid that appears as fine powder. It has a slightly salty, alkaline taste resembling that of sodium carbonate(washing soda). It is also known as baking soda or cooking soda. 

$NaCl + NH _4OH + CO _2\rightarrow NH _4Cl +NaHCO _3$ 

Baking soda is mild base, so when it is added to milk the pH of the milk slightly increases towords basic value.

Baking powder is dry chemical leavening agent a mixture of carbonate or bicarbonate and a weak acid. A typical acid in such formulations is cream of tartar derivative of tartaric acid. Commercially it is sodium bicarbonate.

Baking soda formula is $NaHCO _3$.

Baking soda is sodium bicarbonate or sodium hydrogen carbonate. It has slightly salty, alkaline taste resembling that of washing soda. Its alkalinity in aqueous solution is because of formation of carbonic acid and hydroxide ion.
${ HCO } _{ 3 }^{ - }+{ H } _{ 2 }O\rightarrow { H } _{ 2 }{ CO } _{ 3 }+{ OH }^{ - }$

Tartaric acid used in baking powder where it serves as the source of acid that reacts with baking soda. This reaction produces carbon dioxide gas and lets products rise using active yeast cultures as a source of carbon dioxide gas.

Sodium Bicarbonate (NaHCO3) is called baking soda because when heated, it releases carbon dioxide gas, which is responsible for the rising of cookies, doughnuts, and bread.

Sodium bicarbonate, also commonly known as baking soda, is commonly seen as a white, fine powder and has the chemical formula NaHCO₃. It has one sodium atom, one hydrogen atom, one carbon atom, and three oxygen atoms. It is a very useful chemical that is alkaline in nature.

Sodium bicarbonate 

Baking soda is the common name of Sodium bicarbonate

The reaction between baking soda (sodium bicarbonate) and vinegar (dilute acetic acid) generates carbon dioxide gas and sodium acetate.
$ NaHCO _3 + CH _3COOH \rightarrow  CH _3COONa + H _2O + CO _2 $

The production of carbon dioxide is main characteristic of baking soda that makes it suitable for baking.Baking soda gives carbon dioxide and water vapour on heating at even low temperature such as $1000^oC$. The gas so formed turns lime water milky, which confirms the presence of carbon dioxide gas. When Washing soda ($Na _2CO _3$) is heated it does not produce carbon dioxide even at high temperature, such as $200^0C$ or $300^oC$. However sodium carbonate gives sodium oxide and carbon dioxide when heated at about $1000^oC$.

The gas produced by heating of the samples can be checked by passing through lime water. If the lime water turns milky then the evolved gas is carbon dioxide and the heated substance is baking powder.

$2NaHCO _{3} \xrightarrow{Heat} Na _{2}CO _{3} + H _{2}O + CO _{2}$

$Na _{2}CO _{3}.10H _{2}O \xrightarrow{Heat}Na _{2}CO _{3} + 10H _{2}O$

 Sodium hydrogen carbonate or sodium bicarbonate is used as a fire extinguisher. When heated to a high temperature, the chemical properties of this salt make it produce lots of carbon dioxide and remove oxygen. This reduces the amount of oxygen and puts the fire out. The reaction also produces a small quantity of water and sodium carbonate as by-products.
$2NaHCO _3 + H _2SO _4 \rightarrow Na _2SO _4 + 2H _2O + 2CO _2$

Solution of sodium hydrogen carbonate is mildly alkaline due to the formation of carbonic acid and hydroxide ion:
$ HCO _3 + H _2O \rightarrow H2CO _3 + OH-$ 

Chemical formula of baking soda is $NaHCO _3$.

The carboxylic acids react with baking soda to form sodium acetate, carbon dioxide and water. The general reaction can be written as:
$RCOOH + NaHCO _{3} \rightarrow CH _{3}COONa + CO _{2} + H _{2}O$
Thus the effervescence results from the release of carbon dioxide gas.

Acid in a baking powder can be either fast-acting or slow-acting. $NaAl(SO _4) _2$ is a weak acid, it react with sodiumbicarbonate to produce $CO _2$ gas.

Reaction of process:
$14 NaHCO _3+ 5 Ca(H _2PO _4)2H _2O\rightarrow 14 CO _2+ Ca _5(PO _4)3OH + 7 Na _2HPO _4+ 18 H _2O$

When sodium bicarbonate reacts with $HCl$, chlorine binds with sodium and forms sodium chloride and bicarbonate ion binds with hydrogen ion of $HCl$ and forms carbonic acid. The carbonic acid further dissociates to water and carbon dioxide.

Fire extinguisher contains sodium bicarbonate in water and sulphuric acid in a separate container inside it. When the fire extinguisher is released by pressing the knob on it, the sulphuric acid mixed with sodium bicarbonate solution producing a lot of carbon dioxide gas.

$2NaHCO _3 + H _2SO _4\rightarrow Na _2SO _4 + 2H _2O + 2CO _2$ 

Carbon dioxide gas is neither combustible nor helps in combustion. It is heavier than air and offs the supply of oxygen from air and hence removes the fire. So, sodium bicarbonate is used in fire extinguishers. So the given statement is true.

Hence option A is correct.

Sodium bicarbonate, also called sodium hydrogen carbonate, or bicarbonate of soda,$NaHCO _3$, is a source of carbon dioxide and so is used as an ingredient in baking powders, in effervescent salts and beverages, and as the main constituent of dry-chemical fire extinguishers.

These are the right properties of Sodium Bicarbonate

Soda acid for extinguisher contains sodium hydrogen carbonate and sulphuric acid. The reaction between sodium bicarbonate solution and sulfuric acid expels pressurized water onto a fire.
$2NaHCO _3+H _2SO _4 \rightarrow Na _2SO _4+2H _2O+2CO _2$

• Disodium hydrogenphosphite$ ( Na _2HPO _3)$ is a salt of phosphorus acid $( H _3PO _3)$, which is a dibasic acid. A dibasic acid has only two acidic or replaceable hydrogen atoms in its molecule. In $( H _3PO _3)$, the third hydrogen is directly bonded to phosphorus and so it is non-acidic.
  
• $  Na _2HPO _3$ is formed when the two acidic hydrogens are replaced by sodium. In other words, this salt is the product of complete neutralisation of phosphoric acid by sodium hydroxide. It does not have any acidic hydrogen. So, it can furnish any $H^+$ in its aqueous solution.
  

Sodium bicarbonate mixed with water can be used as an antacid to treat acid indigestion and heartburn. Its reaction with stomach acid produces salt, water, and carbon dioxide: