Magnesium hydrogencarbonate

Such water, and also that containing salts of multipositive metals, (usually sulphates), is said to be hard since it does not readily produce a lather with soap. Experiments with alkali metal salts can be performed to verify that the hardness is due to the presence of the multipositive metal ions and not to any of the anions present. The hardness due to calcium and magnesium hydrogencarbonates is said to be temporary since it can be removed by boiling ... 

There was an attempt to neutralise formic acid by using magnesium hydrogencarbonate. By stirring the medium without care, a violent reaction of the acid with carbonate took place. Carbon dioxide was released in large quantities and caused the projection of the compounds into the surrounding area. 

As this solution passes over and through rocks containing limestone (calcium carbonate, CaCOs) and dolomite (magnesium carbonate, MgCOs), the weak acid in the rain attacks these rocks and very slowly dissolves them. The dissolved substances are called calcium and magnesium hydrogencarbonates. 

Hardness in water can be divided into two types - temporary and permanent. Temporary hardness is caused by the presence of dissolved calcium or magnesium hydrogencarbonates. Temporary hardness is so called because it is easily removed by boiling. 

Stalactites and stalagmites are found in underground caverns in limestone areas. They are formed from the slow decomposition of calcium or magnesium hydrogencarbonates in water (Figure 11.34). 

One of the substances found in some temporary hard waters is magnesium hydrogencarbonate. Write word and balanced chemical equations to show the effect of heat on this substance in aqueous solution. 

An antacid tablet contains 0.1 g of magnesium hydrogencarbonate, MgfHCOjlj. What mass of stomach acid, HCl, will it neutralise ... 

Group II hydrogencarbonates have insufficient thermal stability for them to be isolated as solids. However, in areas where natural deposits of calcium and magnesium carbonates are found a reaction between the carbonate, water and carbon dioxide occurs ... 

Magnesium and calcium hydrogencarbonates are known in solution and are responsible for temporary hardness in water. 

The reaction mixture was transferred into a separating funnel. The aqueous layer was extracted with dichloromethane (10 mL). The combined organic layers were washed with a aqueous solution of sodium hydrogencarbonate (2 x 20 mL), then with water (30 mL), dried over magnesium sulfate, filtered and the solvent removed under reduced pressure. 

Why are cimetidine and ranitidine better antacids than sodium hydrogencarbonate or magnesium or aluminium hydroxide ... 

Saturated solution of sodium hydrogencarbonate Anhydrous sodium sulfate Anhydrous magnesium sulfate Silica gel (10-40 / m)... 

The mixture was cooled to room temperature and transferred into a separating funnel, and then saturated sodium hydrogencarbonate aqueous solution (ca. 20 mL) was added. After the two layers were separated, the aqueous layer was extracted with dichloromethane (3 x lOmL) and the combined organic layers were dried over magnesium sulfate, filtered and concentrated. 

Saturated sodium hydrogencarbonate (100 mL) Anhydrous magnesium sulfate (1 g)... 

Further oxidation of 1-thioglycosides leads to glycosyl sulfones. These have been reported to be activable by magnesium bromide etherate in the presence of sodium hydrogencarbonate.167... 

Hardness in water is caused by the presence of dissolved calcium and magnesium compounds, such as calcium hydrogencarbonate or magnesium sulfate. The hardness of the water can be gauged by its ability to form a thick lather with soap. Water that lathers easily is called soft, whereas water that produces very little lather and a scum, is termed hard. Soap (see page 175) is sodium stearate and scum forms as a result of the precipitation of an insoluble stearate ... 

This type of hard water is called temporary hard water, because it can be removed by boiling. Permanently hard water contains calcium and/or magnesium salts which are not decomposed when the water is boiled. Calcium hydrogencarbonate solution decomposes on boiling to calcium carbonate (scale), which can block pipes or fur kettles in hard water districts ... 

Sodium hydrogencarbonate (aq., sat., 2 X 200 ml) Magnesium sulfate Ether for crystallization... 

In addition to proteins, the plasma contains a large number of other anions, the most predominant of which are chloride and hydrogencarbonate. Smaller amounts of phosphate, sulfate, and organic acids are also present. Plasma also contains a number of cations, most predominantly sodium, and lesser quantities of potassium, calcium, and magnesium. The total cation concentration is 150 mmol 1 , and since electrical neutrality must be maintained, the total anion concentration is similar. However, when subtracting the concentration of the major anions (Cl and HCOi") from the major cations (Na and K ), the result is not zero, but usually between 10 and 20 mmol 1 . This is known as the anion gap and represents the unmeasured anions (e.g., POl , S04, and organic acids). 

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