Monocalcium Phosphate
<p>It is created for fertilizers by treating pulverized phosphate rock with <a href="http://en.wikipedia.org/wiki/Sulfuric_acid" title="Sulfuric acid" >sulfuric acid</a> or <a href="http://en.wikipedia.org/wiki/Phosphoric_acid" title="Phosphoric acid" >phosphoric acid</a>. In labs, it is prepared from the reaction between <a href="http://en.wikipedia.org/wiki/Calcium_carbonate" title="Calcium carbonate" >calcium carbonate</a> with phosphoric acid.</p>
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<a href="http://en.wikipedia.org/wiki/Phosphorus" title="Phosphorus" >Phosphorus</a> is an <a href="http://en.wikipedia.org/wiki/Essential_nutrient" title="Essential nutrient" >essential nutrient</a> and therefore is a common component of agricultural <a href="http://en.wikipedia.org/wiki/Fertilizer" title="Fertilizer" >fertilizers</a>. </p>
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<a href="http://en.wikipedia.org/wiki/Tricalcium_phosphate" title="Tricalcium phosphate" >Tricalcium phosphate</a> Ca<sub >3</sub>(PO<sub >4</sub>)<sub >2</sub> , a major component of <a href="http://en.wikipedia.org/wiki/Phosphate_rock" title="Phosphate rock" class="mw-redirect" >phosphate rock</a> such as <a href="http://en.wikipedia.org/wiki/Phosphorite" title="Phosphorite" >phosphorite</a>,<sup id="cite_ref-0" class="reference" ><a href="http://en.wikipedia.org/wiki/Monocalcium_phosphate#cite_note-0" >[1]</a></sup> <a href="http://en.wikipedia.org/wiki/Apatite" title="Apatite" >apatite</a>, and other <a href="http://en.wikipedia.org/wiki/Phosphate_minerals" title="Phosphate minerals" >phosphate minerals</a>, is too insoluble to be an efficient fertilizer. Therefore it can be converted into the more soluble monocalcium phosphate, generally by the use of <a href="http://en.wikipedia.org/wiki/Sulphuric_acid" title="Sulphuric acid" class="mw-redirect" >sulphuric acid</a> H<sub >2</sub>SO<sub >4</sub>. The result is hydrated to turn the calcium sulphate into the <a href="http://en.wikipedia.org/wiki/Hydrate" title="Hydrate" >dihydrate</a> <a href="http://en.wikipedia.org/wiki/Gypsum" title="Gypsum" >gypsum</a> and sold as <i >superphosphate of lime</i>. Alternately phosphate rock may be treated with phosphoric acid to produce a purer form of monocalcium phosphate and is sold as <i >triple phosphate</i>.</p>
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Calcium dihydrogen phosphate is also used in the food industry as a <a href="http://en.wikipedia.org/wiki/Leavening_agent" title="Leavening agent" >leavening agent</a> to cause baked goods to rise. Because it is acidic, when combined with an alkali ingredient, commonly <a href="http://en.wikipedia.org/wiki/Sodium_bicarbonate" title="Sodium bicarbonate" >sodium bicarbonate</a> (baking soda) or <a href="http://en.wikipedia.org/wiki/Potassium_bicarbonate" title="Potassium bicarbonate" >potassium bicarbonate</a>, it reacts to produce <a href="http://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide" >carbon dioxide</a> and a <a href="http://en.wikipedia.org/wiki/Salt_(chemistry)" title="Salt (chemistry)" >salt</a>. Outward pressure of the carbon dioxide gas causes the rising effect. When combined in a ready-made <a href="http://en.wikipedia.org/wiki/Baking_powder" title="Baking powder" >baking powder</a>, the acid and alkali ingredients are included in the right proportions such that they will exactly neutralize each other and not significantly affect the overall <a href="http://en.wikipedia.org/wiki/PH" title="PH" >pH</a> of the product.</p>