Chemistry: Acids, Bases and Salts

The balanced equation is 2NaOH(aq) + Zn(s) → Na2ZnO2(s) + H2(g).

Carbon dioxide (CO2) gas is produced during the reaction.

Both produce carbon dioxide, but the reaction rate can differ; sodium bicarbonate reacts more slowly than sodium carbonate.

<p>Lime water turns milky or cloudy in the presence of carbon dioxide.</p> Signup and view all the answers

<p>Not all metals can displace hydrogen from sodium hydroxide; it depends on their reactivity.</p> Signup and view all the answers

<p>The odour changes indicate that vanilla can act as an olfactory indicator, showing different scents when mixed with acids and bases.</p> Signup and view all the answers

<p>The surface of the zinc granules became covered in bubbles, indicating the production of hydrogen gas.</p> Signup and view all the answers

<p>Bubbles form because the hydrogen gas gets trapped in the soap solution, creating foam.</p> Signup and view all the answers

<p>The bubbles produce a 'pop' sound and may ignite, indicating the presence of hydrogen gas.</p> Signup and view all the answers

<p>The equation is: Acid + Metal → Salt + Hydrogen gas.</p> Signup and view all the answers

<p>Changes in the scent of clove oil when mixed with dilute HCl and NaOH would indicate its use as an olfactory indicator.</p> Signup and view all the answers

<p>When warmed with sodium hydroxide, zinc may produce hydrogen gas and a zincate ion in solution.</p> Signup and view all the answers

<p>Vanilla and clove oil can be classified as olfactory indicators based on their scent changes in different pH solutions.</p> Signup and view all the answers

<p>A family of salts is defined by having the same positive or negative radicals, such as NaCl and Na2SO4 both being sodium salts.</p> Signup and view all the answers

<p>The number of families can be determined by analyzing the composition of the salts listed.</p> Signup and view all the answers

<p>The pH of salts helps classify them as acidic, basic, or neutral based on their reaction with litmus and their solubility.</p> Signup and view all the answers

<p>Salts with a pH value less than 7, formed from strong acids and weak bases, are classified as acidic.</p> Signup and view all the answers

<p>Sodium chloride, also known as table salt, is formed by the combination of hydrochloric acid and sodium hydroxide.</p> Signup and view all the answers

<p>Rock salt deposits are formed from the evaporation of seawater in ancient oceans, leaving behind large crystals.</p> Signup and view all the answers

<p>Sodium chloride symbolized resistance in the struggle for Indian independence, notably during Mahatma Gandhi's Dandi March.</p> Signup and view all the answers

<p>Litmus paper is used to observe the acidity or basicity of salt solutions, indicating their pH level.</p> Signup and view all the answers

<p>The ideal soil pH for plant growth in my region is typically around neutral, between 6.0 and 7.0, as most plants thrive in this range.</p> Signup and view all the answers

<p>Hydrochloric acid facilitates the breakdown of food and activates digestive enzymes, while the stomach's mucous membrane protects it from the acid.</p> Signup and view all the answers

<p>Antacids neutralize excess hydrochloric acid in the stomach, alleviating pain and discomfort associated with indigestion.</p> Signup and view all the answers

<p>Tooth decay begins when the pH of the mouth drops below 5.5, primarily caused by acid production from bacteria after sugar and food remnants are left in the mouth.</p> Signup and view all the answers

<p>Toothpastes are usually basic to neutralize acids in the mouth, thus preventing tooth enamel corrosion and decay.</p> Signup and view all the answers

<p>The stinging hairs of nettle leaves inject methanoic acid, which causes burning pain upon contact.</p> Signup and view all the answers

<p>Rubbing the affected area with dock plant leaves is a traditional remedy that helps neutralize the methanoic acid from the sting.</p> Signup and view all the answers

<p>Cleaning the mouth after eating helps prevent the buildup of acids, thus maintaining a suitable pH and protecting against tooth decay.</p> Signup and view all the answers

<p>It turns white after heating.</p> Signup and view all the answers

<p>The water droplets come from the moisture in the air or the environment.</p> Signup and view all the answers

<p>The blue color of copper sulphate is restored.</p> Signup and view all the answers

<p>The formula is Cu SO4.5H2O.</p> Signup and view all the answers

<p>There are two water molecules in one formula unit of gypsum.</p> Signup and view all the answers

<p>It produces calcium sulphate hemihydrate, also known as Plaster of Paris.</p> Signup and view all the answers

<p>Water of crystallization affects the physical properties and color of the salts.</p> Signup and view all the answers

<p>It is used to support fractured bones in the correct position.</p> Signup and view all the answers

<p>Fizzing will occur more vigorously in test tube A with hydrochloric acid because HCl is a stronger acid than acetic acid, providing more hydrogen ions for the reaction.</p> Signup and view all the answers

<p>The pH of fresh milk decreases (becomes more acidic) as it turns into curd due to the production of lactic acid during fermentation.</p> Signup and view all the answers

<p>Baking soda is added to shift the pH of fresh milk from 6 to slightly alkaline to enhance its shelf life and prevent spoilage.</p> Signup and view all the answers

<p>Milk takes longer to set as curd because the alkaline environment from baking soda inhibits the activity of lactic acid bacteria needed for curdling.</p> Signup and view all the answers

<p>Plaster of Paris should be stored in a moisture-proof container because it reacts with water to form gypsum, which would ruin its effectiveness.</p> Signup and view all the answers

<p>A neutralization reaction is a chemical reaction between an acid and a base that produces salt and water. Examples include the reaction of hydrochloric acid with sodium hydroxide, and the reaction of acetic acid with sodium bicarbonate.</p> Signup and view all the answers

<p>Washing soda is commonly used for cleaning and as a water softener, while baking soda is used in baking and as an antacid.</p> Signup and view all the answers

<p>When dilute sulphuric acid mixes with sodium bicarbonate, carbon dioxide is produced, which can be directed onto a burning candle to extinguish the flame.</p> Signup and view all the answers