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Acid Bases and Salt Animation

We know that some of the chemical compounds are acidic or alkaline in nature which can be identified with the help of either indicator or pH paper. Let’s discuss how to prepare the animation on acid, base and salt and how will it be useful for learners. Begin the animation with the general properties of acids and bases. Tell the students to observe a graphic showing two brass vessels; one is containing water and the other containing curd. Ask the students which is useful for consumption and which is harmful and why. Observe and note their answers. Explain that the brass vessel having water is healthy for consumption while curd in brass vessel may cause food poisoning.

Discuss the reason as water stored in brass vessels for over 48 hours causes a dramatic fall in the level of microorganisms which are present in drinking water.
Explain that brass is an alloy of copper and zinc. The copper in the alloy gets rid of the harmful microorganisms in water which may cause diarrhoea and other water borne infections.  After that discuss that curd should not be kept in copper or brass vessels because curd is slightly acidic in nature. It is made from milk and thus contains lactic acid.
When kept inside a copper or brass vessels, curd (and other acidic food items) reacts with copper and forms toxic compounds which are unfit for human consumption and cause food poisoning. Therefore we should not keep curd and other acidic or sour food items in copper or brass vessels. Reflect upon the example and ask the students to list the properties by which they can identify an acid.

Now discuss some common properties of acids with students such as corrosiveness, sour in taste, turns blue litmus paper to a red colour. Also discuss the reactions with other indicators like methyl orange, phenolphthalein and odour changing indicators. Some common physical properties of acids are containing hydrogen ions (H+) in aqueous solution, form salts with base, release H2 gas with metal, and for m CO2, H2O and salt with metal carbonates. Ask the students what happens if we suffer from hyperacidity? Explain that in this situation we should take something that nullifies the effect of the acid. The substance that neutralizes acid is called a base. Solution of a base in water forms an alkali. Discuss some common properties of bases such as corrosive nature, soapy feel, and bitter taste, turns red litmus paper to a blue colour and contains hydroxyl ion.

Ask the students to give some examples of bases such as sodium hydroxide or caustic soda or soap, calcium hydroxide or limewater, ammonium hydroxide or ammonia water, magnesium hydroxide or milk of magnesia etc. Conclude that acids and bases are chemicals which have opposite properties. They nullify each other and may be commonly used in our daily lives. Explain what makes a Strong Acid or Strong Base.

The molecule for a strong acid or base cannot exist intact in aqueous solution. It completely dissociates into ions in water. While weak acids or bases are incompletely dissociated in aqueous solutions and intact molecules of weak acid or base also co-exist with the dissociated ions. Discuss that common salt NaCl, a product of strong acid HCl and strong base NaOH has a pH of 7 and is neutral. Discuss Normal or Neutral Salts which are formed by a strong acid and a strong base. A salt that does not contain any replaceable hydrogen ions is called as a normal salt which is obtained by replacing all the H+ ions of an acid by metal ions or ammonium ions. Other examples of salts are NaCl, Na2SO4, Na3PO4, NH4Cl, K2CO3, CuSO4 etc.

Best Results From Wikipedia Yahoo Answers Youtube


From Wikipedia

Acid salt

Acid salt is a somewhat obscure term for a class of salts formed by the partial neutralization of diprotic or polyprotic acids. Because the parent acid is only partially neutralized, one or more replaceable hydrogen ions remain. Typical acid salts have one or more alkali (alkaline) metal ions as well as one or more protons. Well known examples are sodium bicarbonate (NaHCO3), sodium hydrosulfide (NaHS), sodium bisulfate (NaHSO4), monosodium phosphate (NaH2PO4), and disodium phosphate (Na2HPO4). Often acid salts are used as buffers.

For example, the acid salt sodium bisulfate is the main species formed upon the half neutralization of sulfuric acid with sodium hydroxide:

H2SO4 + NaOH → NaHSO4 + H2O

Acid salts compounds can act either as an acid or a base: addition of a suitably strong acid will restore protons, and addition of a suitably strong base will remove protons. The pH of a solution of an acid salt will depend on the relevant equilibrium constants and the amounts of any additional base or acid. A comparison between the Kb and Ka will indicate this: if Kb > Ka, the solution will be basic, whereas if Kb < 'Ka, the solution will be acidic.

Use in food

Some acid salts are used in baking. They are found in baking powders and are typically divided into low-temperature (or single-acting) and high-temperature (or double-acting) acid salts. Common low-temperature acid salts react at room temperature to produce a leavening effect. They include cream of tartar, calcium phosphate, and citrates. High-temperature acid salts produce a leavening effect during baking and are usually aluminium salts such as calciumaluminium phosphate. Some acid salts may also be found in non-dairy coffee creamers.



From Yahoo Answers

Question:i learned that there are three classes of compounds..acids, bases and salts.. But am confused about water's case.. can anyone ans it with reason..pls..

Answers:A SALT HAHAHAH, nah not really its an acid and a base

Question:By looking at a chemical formula, can anyone tell me how to identify whether it is a salt, base or acid?

Answers:acids containds hydrogen so they always have a H infront of it: hydrochloric acid: HCL sulfuric acid: H2SO bases contains hydroxide, so if you see an OH, it is a base: sodium hydroxide: NaOH Calcium Hydroxide: Ca2(OH)2 for salts it depends what kind of salt you're asking. for table salts they are a ionic compound: NaCl hope this helps :)

Question:17.A strong acid reacts with a strong base: acidicbasic neutralimpossible to predict 18.A strong acid reacts with a weak base: acidicbasic neutralimpossible to predict 19.A weak acid reacts with a strong base: acidicbasic neutralimpossible to predict 20.A weak acid reacts with a weak base: acidicbasic neutralimpossible to predict

Answers:17 neutral 18 acidic 19 basic impossible to predict ( Ka and Kb are required)

Question:A. acid B. base C. salt 1. Tastes sour describes a property of _____. (Select all that apply. For example: A,B,C) 2. Feels slippery describes a property of _____. (Select all that apply. For example: A,B,C) 3. Conducts electricity in a solution describes a property of _____. (Select all that apply. For example: A,B,C) 4. Turns blue litmus paper red describes a property of _____. (Select all that apply. For example: A,B,C) 5. Always has a pH greater than 7 describes a property of _____. (Select all that apply. For example: A,B,C) 6. Reacts with active metals to produce hydrogen gas describes a property of (Select all that apply. For example: A,B,C) 7. Is formed by a neutralization reaction describes a property of _____. (Select all that apply. For example: A,B,C) 8. Produces hydroxide ions in water describes a property of _____. (Select all that apply. For example: A,B,C)

Answers:1) A (although some salts are very sour!!!) 2) B 3) C 4) A 5) B 6) A 7) A,B 8) B

From Youtube

Acid Bases and Salts :Check us out at www.tutorvista.com Acids In everyday life we deal with many compounds that chemists classify as acids. For example, orange juice and grapefruit juice contain citric acid. These juices, and others, also contain ascorbic acid, a substance more commonly known as Vitamin C. Salads are often flavored with vinegar, which contains dilute acetic acid. Boric acid is a substance that is sometimes used to wash the eyes. In any chemistry laboratory, we find acids such as hydrochloric acid, sulfuric acid, and nitric acid. These acids are called mineral acids because they can be prepared from naturally occurring compounds called minerals. Mineral acids are generally stronger than household acids, and should be handled with great care because they can burn skin and clothing. Bases: Ammonium hydroxide, or ammonia water, is very irritating to the nose and the eyes. This substance, called a hydroxide, or a base, is often used in the home for cleaning because bases generally dissolve grease. Milk of magnesia (magnesium hydroxide), which is used as an antacid, is a base; lye (sodium hydroxide), which is used in the manufacture of soap, is another familiar example of base. Bases are ionic compounds containing metal ions and hydroxide ions. For example, sodium hydroxide contains sodium ions and hydroxide ions. When sodium metal is placed in water, sodium hydroxide is formed and hydrogen gas is released. Since the formula for water can be written as HOH instead of H2O, the ...

Study Of Acid Bases And Salts :Check us out at www.tutorvista.com An acid (from the Latin acidus meaning sour) is any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, ie a pH less than 7.0 in its standard state. That approximates the modern definition of Johannes Nicolaus Br nsted and Martin Lowry, who independently defined an acid as a compound which donates a hydrogen ion (H+) to another compound (called a base). Common examples include acetic acid (in vinegar) and sulfuric acid (used in car batteries). Acid/base systems are different from redox reactions in that there is no change in oxidation state. Acids can occur in solid, liquid or gaseous form, depending on the temperature. They can exist as pure substances or in solution. Chemicals or substances having the property of an acid are said to be acidic. In chemistry, a base is most commonly thought of as an aqueous substance that can accept hydrogen ions. Bases are also the oxides or hydroxides of metals. A soluble base is also often referred to as an alkali if hydroxide ions (OH ) are involved. This refers to the Br nsted-Lowry theory of acids and bases. Alternative definitions of bases include electron pair donors (Lewis), and as sources of hydroxide anions (Arrhenius). In addition to this, bases can commonly be thought of as any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity lower than that of pure water, ie a pH higher than ...