Guar gum is needed for producing sufficient viscosity. Because less is required, costs are reduced. This would help explain its presence in so many things today. In addition to guar gum's effects on viscosity, its high ability to flow, or "deform", gives it very favorable rheological properties. It forms breakable gels when cross-linked with boron. It is used in various multi-phase formulations for hydraulic fracturing, in some as an emulsifier because it helps to prevent oil droplets from coalescing, and in others as a stabilizer to help prevent solid particles from settling and/or separating. Fracking entails the pumping of sand-laden fluids into
Hydrochloric acid (roughly 20.2%) can be used as a primary standard in quantitative analysis, although its exact concentration depends on the atmospheric pressure when it is prepared. Hydrochloric acid is frequently used in chemical analysis to prepare ("digest") samples for analysis. Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas. It also reacts with basic compounds such as calcium carbonate or copper(II) oxide, forming the dissolved chlorides that can be analyzed. Physical properties of hydrochloric acid, such as boiling and melting points, density, and pH, depend on the concentration or molarity of HCl in the aqueous solution.