The reaction of sodium chloride

Chemical properties of table salt

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Sodi­um chlo­ride or sodi­um salt of hy­drochlo­ric acid is a pow­der or crys­tals of a col­or­less, odor­less sub­stance, with a salty taste. In ev­ery­day life, sodi­um chlo­ride is known as ta­ble salt. The chem­i­cal for­mu­la is NaCl. In na­ture it is en­coun­tered in the form of halite, i.e. rock salt. Pure sodi­um chlo­ride is col­or­less, but if it con­tains im­pu­ri­ties, it may take on oth­er col­ors. For ex­am­ple, it may be pur­ple or blue, yel­low or pink.

Phys­i­cal prop­er­ties of sodi­um chlo­ride

It is mod­er­ate­ly sol­u­ble in wa­ter, and the tem­per­a­ture at which the re­ac­tion takes place plays prac­ti­cal­ly no role. At a tem­per­a­ture of 21 °C the co­ef­fi­cient of sol­u­bil­i­ty in 100g of wa­ter is 35.9, at 100 C it is 38.1 Chlo­ride ions form a cu­bic lat­tice, with sodi­um ions are at the top. Melt­ing point is 800.8 °C. Ta­ble salt be­gins to boil at a tem­per­a­ture of 1,465 °C.

Chem­i­cal prop­er­ties of the sodi­um salt of hy­drochlo­ric acid

NaCl is a salt which was formed as a re­sult of the in­ter­ac­tion of an al­ka­li and acid. Sodi­um chlo­ride is a strong elec­trolyte. The ions at­tract each oth­er very strong­ly, and the at­trac­tion be­tween them can only be bro­ken by po­lar sol­vents. In H₂O the crys­tal lat­tice eas­i­ly falls apart. An­ions and cations of the bond are freed (Na⁺, Cl⁻). This ex­plains the good elec­tri­cal con­duc­tiv­i­ty of sodi­um chlo­ride.

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Qual­i­ta­tive re­ac­tions to sodi­um cations

The qual­i­ta­tive re­ac­tion to de­ter­mine the sodi­um cation Na⁺

Take a wire and make a loop at the end of it. Put a lit­tle salt on the loop and hold it up to a flame. The flame will burn with a yel­low col­or – this shows the pres­ence of sodi­um.

An­oth­er re­ac­tion for the sodi­um cation

Diox­oura­ni­um(VI) zinc ac­etate forms a yel­low crys­talline sed­i­ment. The chem­i­cal re­ac­tion is:

NaCl + Zn(UO₂)₃(CH₃­COO)₈ + CH₃­COOH + 9H₂O ↔ NaZn(UO₂)₃(CH₃­COO)₉ · 9H₂O↓ + HCl

Re­ac­tion of potas­si­um hex­ahy­drox­oan­ti­monate(V)

A white sed­i­ment forms, which is sol­u­ble in al­ka­lis:

NaCl + K[Sb(OH)₆] ↔ Na[Sb(OH)₆]↓ + KCl

In an acid medi­um, the reagent breaks down with the for­ma­tion of a white amor­phous sed­i­ment of meta-an­ti­mon­ic acid HS­bO₃:

K[Sb(OH)₆] +HCl ↔ KCl + H₃S­bO₄ + 2H₂O

H₃S­bO₄ ↔ HS­bO₃↓ + H₂O

Qual­i­ta­tive re­ac­tion to the pres­ence of an an­ion, i.e. Cl⁻

This can be ob­served in the qual­i­ta­tive re­ac­tion to chlo­ride ions. In the in­ter­ac­tion with sil­ver ni­trate, a sed­i­ment of sil­ver chlo­ride of a white col­or forms. The chem­i­cal for­mu­la is:

Ag­NO₃ + NaCl = AgCl + NaNO₃

Silver chloride molecule [Wikimedia]

Hy­dro­gen chlo­ride from the salt is forced out by stronger acids than hy­drochlo­ric acid. The chem­i­cal re­ac­tion is:

2Na­Cl + H₂­SO₄ = Na₂­SO₄ + 2HCl

Quan­ti­ta­tive de­ter­mi­na­tion of sodi­um chlo­ride

We take a stan­dard so­lu­tion of sodi­um chlo­ride and pour it into a flask, di­lute it with two parts dis­tilled wa­ter, add two drops of potas­si­um chro­mate so­lu­tion and titrate with a so­lu­tion of sil­ver ni­trate un­til an or­ange-yel­low col­or ap­pears:

NaCl + Ag­NO₃ → AgCl↓ + NaNO₃

Sodium chloride [Wikimedia]

An­oth­er method for the re­ac­tion of sodi­um chlo­ride and de­ter­min­ing the quan­ti­ty of salt. Mix a sodi­um chlo­ride so­lu­tion in a flask for titra­tion, add 4 drops of di­lut­ed ni­tric acid (1:4), 4 drops of a sat­u­rat­ed al­co­hol so­lu­tion of diphenyl­car­bazone. Start to titrate with a 0.01 M so­lu­tion of mer­cury per­chlo­rate un­til a pink­ish-pur­ple col­or ap­pears.

Click here to see more ex­per­i­ments with sodi­um chlo­ride.

Lo­ca­tion of ta­ble salt

There is a suf­fi­cient quan­ti­ty of sodi­um chlo­ride on Earth. It can be found:

  1. In the wa­ter of seas, oceans and lakes. The world ocean con­tains 120 bil­lion tons of sodi­um chlo­ride. 1.3 tons of sodi­um chlo­ride can be ob­tained for 1,000 tons of sea wa­ter.
  2. There are many de­posits of this min­er­al in var­i­ous coun­tries, and the largest de­posit can be found in Great Britain.
  3. On the shores of salt lakes.
  4. In salt marsh­es
  5. On the walls of vol­cano craters.

Use and ben­e­fit of salt for hu­man be­ings

Kitchen salt is used for salt­ing veg­eta­bles, fish and meat. It is used as an­ti­sep­tic.

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The role of sodi­um chlo­ride is also im­por­tant in medicine; it is used for an iso­ton­ic so­lu­tion. 9 g of salt is di­lut­ed in 1 liter of wa­ter. This is the con­cen­tra­tion of chlo­ride so­lu­tion found in the hu­man body: in liq­uid and tis­sues. So­lu­tions with high­er con­cen­tra­tions are used as an­timi­cro­bial agents, and also to pre­vent rot­ting and fer­men­ta­tion.

De­spite its many pos­i­tive char­ac­ter­is­tics, in large amounts salt is very harm­ful and poi­sonous for chick­ens, dogs and cats. Hu­mans are also not rec­om­mend­ed to con­sume a lot of salt, as this may cause tis­sue swelling.