Hydrogen chloride - class-XII

Aqua regia is also called as royal water is a mixture of nitric acid and hydrochloric acid in the  molar ratio of 1:3. Aqua regia is a yellow-orange fuming liquid.Aqua regia is used for the decomposition of weak acids.

Hene option D is correct.

When glass rod dipped in $NH _3$, it is $HCl$ which reacts to form $NH _4Cl$ and when dipped in $HCl$, it is $NH _3$ which react to form $NH _4Cl$. 

When vanilla extract is added to dil. HCl, it still retains the sweet pleasant smell. Its smell changes when added to a base.

An acid is a substance that can donate a hydrogen ion ($H^+$) or proton to another substance. $HCl$ can donate proton so it is a acid.

Zn being an active metal it readily reacts HCl at room temperature.

Aqua regia is a mixture of hydrochloric acid and nitric acid in the ration $3:1$. It is a very strong acid and can dissolve any metals including noble metals like gold and silver.

Hydrochloric acid was earlier called muriatic acid. Gay-Lussac coined the name hydrochloric acid in the year 1814.

Concentrated hydrochloric acid or fuming HCl acid forms acidic mists. Both the mist and the solution have a corrosive effect on human tissue like eyes, skin, intestines etc. This moisture can be prevented during the preparation of HCl by using a guard tube with calcium chloride in it.

$HCl$ can produce ions only in aqueous solution making aqueous $HCl$acidic. So, aqueous $HCl$ turns blue litmus red whereas dry $HCl$ does not dissociate and acts inert to litmus.

Aqua regia, or nitro-hydrochloric acid is a highly corrosive mixture of acids, a fuming yellow or red solution. The mixtures is formed by freshly mixing concentrated nitric acid and hydrochloric acid hoptimally in a volume ratio of 1:3. It was named so because it can dissolve the noble metalsgold and platinum
Hence answer 1 is correct.

The pH of acids is given by the pH scale from 1-7. Strength of acids increases by moving down the scale from 7 to 1. High acidity ranks as 1 on the pH scale and 7 are neutral. HCl is highly acidic so it has pH less than 7 while on this scale basicity increases going from 7 to 14. So all the acids have pH under 7.

Metals that are more reactive than hydrogen, such as magnesium, react with hydrochloric acid to produce a metal chloride salt and hydrogen gas.

HCl is covalent in the gaseous state but dissociates into ions in aqueous solution. It behaves like acid when aqueous.

In the free state HCl gas is found in the trace amount in volcanic regions.

Both zinc and magnesium conduct electricity. Both zinc and magnesium reacts with hydrochloric acid to give hydrogen gas. They can be distinguished by measuring their densities.

$HCl$ is available in free state in volcanic gases and it is also available in gastric juices of mammals and helps in digestion process of mammals.

Mutaric acid is the name given to the hydrochloric acid by Lavoisier

$HCl$ is present in free state in volcanic emissions and it is also available in gastric juices of mammals and helps in digestion process.
Hence option C is correct.

HCl is a covalent compound which dissociates to form hydrogen and chloride ions. Benzene and toluene undergo electrophilic aromatic substitution reaction when chloride ion binds to the benzene ring forming aryl halides.

$Mn{ O } _{ 2 }+4HCl\longrightarrow Mn{ Cl } _{ 2 }+{ Cl } _{ 2 }$
Oxidation state of $Cl$ on the product side is $-1,0$

Aqueous $HCl$ is ionized as $H^{+},Cl^{-}$ which allows the electricity to flow  where as all other $HCl$ is available as unionized form which do not allow the electricity to pass.
Hence option $B$ is correct.

${ Na } _{ 2 }C{ O } _{ 3 }+HCl\longrightarrow NaCl+{ H } _{ 2 }O+C{ O } _{ 2 }$
Carbonates reacts with $HCl$ gives $C{ O } _{ 2 }$

M.W. of $H$ $=1$ g 
M.W. of $Cl$ $=35.5$ g 

Hydrochloric acid is a clear, colorless, highly pungent solution of hydrogen chlorine in water. It is also known as spirit of salt and muriatic acid.

Metals below hydrogen in the reactivity series, such as copper, cannot displace hydrogen from dilute acids. Aluminium, iron, zinc, and magnesium are all more reactive than hydrogen.

Acidic nature of $HCl$ is due to hydrogen ions which reacts with water to form hydronium ions. 
$HCl(g) +{ H } _{ 2 }O \rightleftharpoons { H } _{ 3 }{ O }^{ + }+{ Cl }^{ - }$

1. $HCl\left( g \right) +{ H } _{ 2 }O\rightleftharpoons { H } _{ 3 }{ O }^{ + }+{ Cl }^{ - }$
   2) ${ 2KMnO } _{ 4 }+16HCl\rightarrow { 2MnCl } _{ 2 }+{ 8H } _{ 2 }O+2KCl+{ 5Cl } _{ 2 }$
   3) $ { MnO } _{ 2 }+4HCl\rightarrow { MnCl } _{ 2 }+{ Cl } _{ 2 }+2{ H } _{ 2 }O$
   4) $Zn\left( OH \right) _{ 2 }+{ H }Cl\rightarrow { ZnCl } _{ 2 }+{ H } _{ 2 }O$
   All of the above equation shows the acidic properties of hydrochloric acid.

Hydrochloric acid has a pungent smell and is a colourless gas.

Statement I : The reactivity of powdered zinc will be greater than the larger piece of zinc of the same mass with HCl.
Statement II : The  powdered zinc has more surface area than the larger piece of zinc of the same mass. Higher is the surface area, higher is the reactivity.

$\displaystyle H _2$ and $\displaystyle Zn^{2+}$ is produced by the reaction of zinc metal, $Zn$, and hydrochloric acid, $HCl$.
$\displaystyle Zn + 2HCl  \rightarrow ZnCl _2 + H _2$

Metals that come before hydrogen in the reactivity series form their corresponding chlorides when heated with HCl and liberate hydrogen gas.

$CaO+2HCl \rightarrow CaCl _2+H _2O$

Concentrated hydrochloric acid fumes in the air forming acidic mists. Both the mist and the solution have a corrosive effect on human tissue with the potential to damage respiratory organs, eyes, skin and intestines.

Hydrochloric acid is used in chemical analysis to prepare sample for analysis. Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas but it does not react with all metals.

Physical properties of $HCl$ acid such as boiling point and melting points, density and pH depend upon the concentration or molarity of $HCl$ in the aqueous solution. They range from those of water at very low conc. approaching 0% $HCl$ to values for fuming $HCl$ over 40% $HCl$.