Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 262

Put the bichromate of potash into the 10,000 grain flask, and, having half filled the flask with water, allow the salt to dissolve; then dilute the solution with more water, until it has the exact bulk of 10,000 grain-measures: 1000 grain-measures of this solution contain 1475 grains of the bichromate (1/10th of K_{2}CrO_{3}, or 1/20th of K_{2}Cr_{2}O_{7} in grains), and, when added to a solution of a protosalt of iron, acidulated with hydrochloric acid, are capable of converting 168 grains (1/10th of 6Fe, or 1/20th of 6Fe in grains) from the state of protosalt to that of persalt grammes, and cubic centimetres may be employed instead of grains and grain-measures; but for convenience 1/10th of the numbers should be taken. Thus, 1475 grammes of bichromate of potash should be made to form 1000 cubic centimetres of solution. 100 cubic centimetres of this solution contain 1475 grammes of the bichromate (1/100th of KO,2CrO_{3}, or 1/200th of K_{2}Cr_{2}0_{7} in grammes), and, when added to a solution of protosalt of iron acidulated with hydrochloric acid, are capable of converting 168 grammes of iron (1/100th of 6Fe, or 1/200 of 6Fe, in grammes) from the state of protosalt to that of persalt.

This solution is used for determining the proportion of protoxide of iron in the following preparations. It is known that the whole of the protosalt has been converted into a persalt when a minute drop of the liquid, placed in contact with a solution of red prussiate of potash on a white plate, ceases to strike with it a blue colour.

British Weights Metrical Weights and Measures. and Measures.

/-----------/------------- or /---------/-------- Grains weight = Grain measures Grams weight = C. C. of of substance. of vol. sol. of substance. vol. sol.

Ferri a.r.s.enias 20 = 170 or 20 = 170 " carb. sacch. 20 = 330 " 20 = 330 " oxid. magn. 20 = 83 " 20 = 83 " Phosphas 20 = 250 " 20 = 250

VOLUMETRIC SOLUTION OF HYPOSULPHITE OF SODA (hyposulphite of soda crystallised, NaO_{1}S_{2}O_{2} + 5HO = 124, or Na_{2}H_{2}S_{2}O_{4}.4H_{2}0 = 248).

Take of-- Hyposulphite of soda, in crystals 280 grains.

Distilled water a sufficiency.

Dissolve the hyposulphite of soda in 10,000 grain-measures of water. Fill a burette with this solution and drop it cautiously in 1000 grain-measures of the volumetric solution of iodine until the brown colour is just discharged. Note the number of grain-measures (_n_) required to produce this effect; then put 8000 grain-measures of the same solution into a graduated jar, and augment this quant.i.ty by the addition of distilled water until it amounts to (8000 1000) / _n_ grain-measures. If, for example, _n_=950, the 8000 grain-measures of solution should be diluted to the bulk of (8000 1000) / 950 = 8421 grain-measures.

1000 grain-measures of this solution contains 248 grains of the hyposulphite (1/10th of 2(NaO,S_{2}O_{2} + 5HO), or 1/10th of =Na_{2}H_{2}S_{2}O_{4},4H_{2}O= in grains), and therefore corresponds to 127 grains of iodine (1/10th of an equivalent).

Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 1/10th of the numbers should be taken.

100 cubic centimetres of this solution contain 248 grammes of the hyposulphite (1/100 of 2(NaO,S_{2}O_{2}+ 5HO), or 1/100th of Na_{2}H_{2}S_{2}O_{4}.4H_{2}O in grammes), and therefore corresponds to 127 grains of iodine (1/100th of an equivalent).

This solution is used for testing the following substances. In each case, except that of iodine, a solution of iodide of pota.s.sium and hydrochloric acid are added to the substance, and the amount of iodine so liberated is indicated by this solution:

British Weights Metrical Weights and Measures. and Measures.

/------------/------------ or /---------/--------- Grains weight = Grain-measures Grams weight = C. C. of of substance. of vol. sol. of substance. vol. sol.

Calx Chlorata 100 = 850 or 100 = 850 Iodum 127 = 1000 " 127 = 1000 Liq. calc. chloratae 600 = 500 " 600 = 500 Liq. chlori 4390 = 750 " 4390 = 750 Liq. Sodae chloratae 700 = 500 " 700 = 500

VOLUMETRIC SOLUTION OF IODINE (iodine, I = 127, or I = 127).

Take of iodine 127 grains.

Iodide of pota.s.sium 180 "

Distilled water a sufficiency.

Put the iodide of pota.s.sium and the iodine into the 10,000 grain flask, fill the flask to about two thirds its bulk with distilled water, gently agitate until solution is complete, and then dilute the solution with more water, until it has the exact volume of 10,000 grain-measures. 1000 grain-measures of this solution contain 1/10th of an equivalent in grains (127 grains) of iodine, and therefore correspond to 17 grains of sulphuretted hydrogen, 32 grains of sulphurous acid, and 495 grains of a.r.s.enious acid.

Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 1/10th of the numbers should be taken.

100 cubic centimetres contain 127 grammes of iodine, and correspond to 017 grammes of sulphuretted hydrogen, 032 grammes of sulphurous, and 0495 grammes of a.r.s.enious acid. This solution is for testing the following substances. It is dropped from the burette into the liquid to be tested, until free iodine begins to appear in the solution.

British Weights Metrical Weights and Measures. and Measures.

/------------/------------ or /---------/-------- Grains weight = Grain-measures Grams weight = C. C. of of substance. of vol. sol. of substance. vol. sol.

Acid. a.r.s.enios 40 = 808 or 040 = 808 Acid. sulphurosum 347 = 1000 " 347 = 1000 Liquor a.r.s.enicalis 4415 = 808 " 4415 = 808 Liquor a.r.s.enici } hydrochloricus} 4415 = 810 " 4415 = 810

VOLUMETRIC SOLUTION OF NITRATE OF SILVER (nitrate of silver, AgO, NO_{5} = 170, or AgNO_{3}* = 170).

Take of nitrate of silver 170 grains.

Distilled water a sufficiency.

Put the nitrate of silver into the 10,000 grain flask, and having filled half the flask with water, allow the salt to dissolve; then dilute the solution with more water until it has the exact bulk of 10,000 grain-measures.

The solution should be kept in an opaque stoppered bottle. 1000 grain-measures of this solution contain 1/10th of an equivalent in grains of nitrate of silver (or 170 grains). Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 1/10th of the numbers should be taken. 100 cubic centimetres contain 1/10th of an equivalent in grammes of nitrate of silver (or 17 grammes).

It is used in testing the following substances.

British Weights Metrical Weights and Measures. and Measures.

/------------/------------ or /--------/--------- Grains weight = Grain-measures Grams weight = C. C. of of substance. of vol. sol. of substance. vol. sol.

Acid. hydrocyan. 270 = 1000 or 270 = 1000 Pota.s.s. bromid. 10 = 840 " 10 = 840 Sodae a.r.s.enias (dry) 10 = 1613 " 10 = 1613

VOLUMETRIC SOLUTION OF OXALIC ACID (crystallised oxalic acid, 2HO, C_{4}H_{6} + 4HO = 126, or H_{2}C_{2}O_{4}2H_{2}O = 126). Take of--

Purified oxalic acid in } crystals, quite dry, but } 630 grains.

not effloresced } Distilled water a sufficiency.

Put the oxalic acid into the 10,000 grain flask, fill the flask to about two thirds of its bulk with water, allow the acid to dissolve, and then dilute the solution with more water until it has the exact volume of 10,000 grain-measures. 1000 grain-measures of this solution contain half an equivalent in grains (63 gr.) of oxalic acid, and are therefore capable of neutralising an equivalent in grains of an alkali or alkaline carbonate. Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 1/10th of the numbers should be taken. 100 cubic centimetres contain 1/20th of an equivalent in grammes (63 grammes) of oxalic acid, and will neutralise 1/10th of an equivalent in grammes of an alkali. The following substances are tested with this solution:

British Weights Metrical Weights and Measures. and Measures.

/-------/------- or /--------/-------- Grains = Grain- Grams = C. C. of weight of measures weight of vol. sol.

substance. of vol. sol. substance.

Ammoniae carb. 590 = 1000 or 590 = 1000 Borax 1910 = 1000 " 1910 = 1000 Liq. ammon. 850 = 500 " 850 = 500 Liq. ammon. fort. 523 = 1000 " 523 = 1000 Liq. calcis 43800 = 200 " 43800 = 200 Liq. calcis sacchar 4602 = 254 " 4602 = 254 Liq. plumbi subacet. 4133 = 810 " 4133 = 810 Liq. pota.s.sae 4629 = 482 " 4629 = 482 Liq. pota.s.sae efferves. 43800 = 150 " 43800 = 150 Liq. sodae 4580 = 470 " 4580 = 470 Liq. sodae efferves. 43800 = 178 " 43800 = 178 Plumbi acetas 380 = 200 " 380 = 200 Pota.s.sa caustica 560 = 900 " 560 = 900 Pota.s.sae bicarb. 500 = 500 " 500 = 500 Pota.s.sae carb. 830 = 980 " 830 = 980 Pota.s.sae citras 1020 = 1000 " 1020 = 1000 Pota.s.sae tartras 1130 = 1000 " 1130 = 1000 Pota.s.sae tartras acida 1880 = 1000 " 1880 = 1000 Soda caustica 400 = 900 " 400 = 900 Soda tartarata 1410 = 1000 " 1410 = 1000 Sodae bicarb. 840 = 1000 " 840 = 1000 Sodae carb. 1430 = 960 " 1430 = 960

VOLUMETRIC SOLUTION OF SODA (hydrate of soda, NaO, HO = 40, or NaHO = 40).

Take of solution of soda a sufficiency.

Distilled water a sufficiency.

Fill a burette with the solution of soda, and cautiously drop this into 63 gr. of purified oxalic acid, dissolved in about 2 oz. of water, until the acid is exactly neutralised as indicated by litmus.

Note the number of grain-measures (_n_) of the solution used, and having then introduced 9000 grain-measures of the solution of soda in a graduated jar, augment this quant.i.ty by the addition of water until it becomes

9000 1000 / _n_ grain-measures =

If, for example, _n_ = 930, the 9000 grain-measures should be augmented to

9000 1000 / 930 = 9,677 grain-measures.

One thousand grain-measures of this solution contain one equivalent in grains (40 gr.) of hydrate of soda, and will therefore neutralise one equivalent in grains of any mon.o.basic acid.

Grammes and cubic centimetres may be employed, instead of grains and grain-measures; but for convenience 1/10th of the numbers should be taken.

1000 cubic centimetres contain 1/10th of an equivalent in grammes (4 grammes) of hydrate of soda, and will neutralise 1/10th of an equivalent in grammes of an acid.

This solution is used for testing the following substances:

British Weights Metrical Weights and Measures. and Measures.

/--------/------- or /--------/-------- Grains = Grain- Grams C. C. of weight of measures weight of = vol. sol.

substance. of vol. substance.

sol.

Acetum 4454 = 402 or 4454 = 402 Acid. acet. 1820 = 1000 " 1820 = 1000 Acid. acet. dil. 4400 = 313 " 4440 = 313 Acid. acet. glac. 600 = 990 " 600 = 990 Acid. citric 700 = 1000 " 700 = 1000 Acid. hydrochloric 1148 = 1000 " 1448 = 1000 Acid. hydrochloric dil. 3450 = 1000 " 3450 = 1000 Acid. nitric 900 = 1000 " 900 = 1000 Acid. nitric dil. 3613 = 1000 " 3613 = 1000 Acid. nitro-hydrochlor. dil. 3524 = 920 " 3524 = 920 Acid. sulph. 506 = 1000 " 506 = 1000 Acid. sulph. arom. 3042 = 830 " 3042 = 830 Acid. sulph. dil. 3590 = 1000 " 3590 = 1000 Acid. tart. 750 = 1000 " 750 = 1000