Acids, Bases and Salts Test - 2

Reaction: \(4 \mathrm{Fe}+10 \mathrm{HNO}_{3} \rightarrow 4 \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}+3 \mathrm{H}_{2} \mathrm{O}+\mathrm{NH}_{4} \mathrm{NO}_{3}\)

It forms ferrous nitrate and ammonium nitrate along with the removal of water.

Hence, option \(C\) is correct.

Acids have a general property to release hydrogen ion H⁺ in the solution medium, due to which they turn the blue litmus red.

Dissociation of CH₃OH (methanol) won't produce enough protons/hydrogen ions to shift the equilibrium towards the acidic side and hence it won't affect the colour of the litmus solution.

Acetic acid (CH₃COOH) undergoes dissociation to release hydrogen ions which makes it acidic in nature.

Thus, it can change the colour of blue litmus solution to red.

CH3COOH $\to$CH3COO^-1 + H⁺

However, in case of CH₃COOCH₃ and CH₄, the hydrogen atoms are covalently bonded to the carbon atoms and hence they are not released as hydrogen ions in the solution, thus they do not change the colour of the litmus solution

Hence, the correct answer is the option (B).

Sodium chloride imparts a yellow color to the Bunsen flame. This can be interpreted due to the emission of excess energy absorbed as a radiation in the visible region.

When an alkali or akaline earth metal (or its salt) is introduced in the flame, the valence electrons of the metal absorbs energy and are excited to the higher energy level. When excited electrons return to their ground state, they release the absorbed energy as visible light.

Citric acid is found naturally in citrus fruits, especially lemons and limes. It’s what gives them their tart, sour taste.

A manufactured form of citric acid is commonly used as an additive in food, cleaning agents, and nutritional supplements.

However, this manufactured form differs from what’s found naturally in citrus fruits.

Solutions of acids and bases produce some ions that can carry electric current, so they are said to be electrolytes.

Acids contain at least one hydrogen atom that can be removed when the acid is dissolved in water. An acid is a substance that produces hydrogen ions in a water solution. When an acid dissolves in water, hydrogen ions interact with water to form hydronium ions.

The strength of an acid or base depends on how many acid or base particles dissociate into ions in water. When a strong acid dissolves in water all molecules ionize into ions. When a weak acid dissolves in water a small fraction dissolve in water.

If the Ph value of a solution is zero, then it means the solution is strongly acidic in nature. 

Acidic nature of the acid is determined when the ph value of the solution turns to be zero. This means that the number of the hydrogen cations are of high concentration in the solution.

As given :  8 mL of HCl solution is required to neutralise 10 mL of NaOH.

So as usual to neutralise 20 mL of same solution i.e. of NaOH we would need 16 mL of same solution of HCl.

Hydrogen ion concentration (the pH) is one of the important factors that affect growth and multiplication of algae and hence the oil and biodiesel production. Most algal growth occurs in the region of neutral pH, although optimum pH is the pH of initial culture in which an alga is adapted to grow . Bartley et al. found that pH of around 8 seems most beneficial for maximum growth rate and lipid accumulation of Nannochloropsis salina and to minimize invading organisms. However, adding buffers will not be cost-effective or realistic at a large scale. They also demonstrated that higher pH values per se do not slow Nannochloropsis production. Thus, the addition of CO2 at large scales is mostly valuable for providing an inorganic carbon source for algae.

Moheimani found pH 7 and 7.5 to be ideal for lipid accumulation in Tetraselmis suecica and Chlorella sp. While, Bartley et al. [146] found no significant effect of pH change on lipid accumulation, the treatment with a pH change to 8 exhibited the greatest overall accumulation (averaging 24.75% by mass) of N. salina. Rodolfi et al. found the lipid content (% biomass) for different Nannochloropsis spp. to be 24.4–35.7%. The earlier results indicate that pH may not be an important stress factor that triggers increased lipid accumulation in microalgae. Acidic pH of culture media can alter nutrient uptake or induce metal toxicity and therefore have an effect on algal growth and oil production . The green microalga Chlamydomonas acidophila and the diatom Pinnularia braunii accumulate storage lipids, such as triacylglycerides, under extremely acidic environment (pH 1). However, basic pH decreases membrane-associated polar lipids due to cell cycle inhibition. In basic pH conditions, membrane lipids in Chlorella were observed to be less unsaturated.

Acidic

Reason: Phenolphthalein is a chemical compound with the formula \(C_{20} H_{14} O_{4}\). It is commonly used as an acid-base indicator for titrations. lt is a weak acid.

Ammonia is a chemical compund with the formula NH₃. Usually, it's a colorless gas with a pungent odor and is seen in some houshold cleaning solutions. Ammonia is a colorless and pungent gas composed of nitrogen and hydrogen.

At first glance, aluminum chloride appears to be an inorganic salt with the empirical formula AlCl₃; however, aluminum, like other group III elements, tends to form covalent bonds with halides.

The most common salt, sodium chloride (NaCl), is a product of the reaction between hydrochloric acid (HCl) and the base sodium hydroxide (NaOH). In this reaction, positively charged hydrogen ions (H⁺) from the acid are attracted to negatively charged hydroxyl ions (OH^-) from the base. These ions combine and form water.

The main use of litmus is to test whether a solution is acidic or basic. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F). Neutral litmus paper is purple.

PH paper is used to determine if a solution is acidic, basic or neutral. This is determined by dipping part of the paper into a solution of interest and watching the color change. The packages that pH paper comes in often includes a color-coded scale indicating the pH that something has when the paper turns a certain color. For instance, if the paper turns a dark greenish-blue, the pH may likely be around 11 to 14.

Toothpaste is a paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, assists in suppressing halitosis, and delivers active ingredients (most commonly fluoride) to help prevent tooth decay (dental caries) and gum disease (gingivitis). Salt and sodium bicarbonate (baking soda) are among materials that can be substituted for commercial toothpaste. Large amounts of swallowed toothpaste can be toxic.

In alkaline solution, phenolphthalein gives pink color as it works as an indicator which shows its endpoint when it reacts with hydroxide ions of the base. It is a commonly used indicator in acid-base titrations. In acidic solution when acid is added, phenolphthalein gives a colorless solution.

Sodium carbonate, Na₂CO₃, (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na₂CO₃ and its various hydrates. All forms are white, water-soluble salts. All forms have a strongly alkaline taste and give moderately alkaline solutions in water. Historically it was extracted from the ashes of plants growing in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood (once used to produce potash), sodium carbonate became known as "soda ash." It is produced in large quantities from sodium chloride and limestone by the Solvay process.

The decahydrate is formed from water solutions crystallizing in the temperature range -2.1 to +32.0 C, the heptahydrate in the narrow range 32.0 to 35.4 C and above this temperature the monohydrate forms. In dry air the decahydrate and heptahydrate lose water to give the monohydrate. Other hydrates have been reported, e.g. with 2.5 units of water per sodium carbonate unit ("pentahemihydrate").

Name the compound which is obtained from baking soda and is used to remove permanent hardness of water. Sodium Carbonate also known as washing soda is used to remove the permanaent hardness of water.

\(N_{1} V_{1}=N_{2} V_{2}\)

\(0 \cdot 1 \times 20=N_{2} V_{2}\)

\(N_{2} V_{2}=2\)

\(N_{2}=\frac{w_{2}}{\frac{M \cdot w t}{2}} \times \frac{1000}{V_{2}(m l)}\)

\(N_{2} V_{2}=\frac{w_{2}}{\frac{126}{2}} \times 1000\)

\(2=\frac{w_{2}}{126} \times 2 \times 1000\)

\(w_{2}=\frac{126}{1000}\)

\(w_{2}=0 \cdot 126 g\)

Chemical Double Decomposition:

When two aqueous solution react with each other and produce a precipitate is called as double decomposition reaction

Example:

\(M g C l_{2}(a q)+2 K O H_{(a q)} \rightarrow M g(O H)_{2}+2 K C l_{(s a l t)}\)

Water chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid.

Slaked lime and sulphuric acid acid-base pairs reacts to produce calcium sulphate.

If a solution of dilute hydrochloric acid is added to concentrated hydrochloric acid, then concentration of hydrogen ions will increase and that of hydroxyl ions will decrease.

Magnesium Hydroxide [Mg(OH)2] – Magnesium hydroxide is best known as milk of magnesia. Like magnesium citrate or magnesium sulfate, it is an effective laxative. Were it not for its tendency to cause diarrhea, magnesium hydroxide would be the most ideal antacid. To counter the diarrhea effect, most manufacturers add aluminum hydroxide, which is constipating. The combination substantially raises the price, and the addition of the less-effective aluminum hydroxide reduces the antacid benefit.

When the sodium hydroxide, which is a base, is mixed with phenolphthalein, it turns pink. This happens because the base is neutralized in an acid solution, which causes the indicator to become colorless.

Potato plants  prefer to grow in the area where soil shows a wide range of pH value from 5.3 to 6.0.

A molecular ion is a covalently bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zero. Unlike a molecule, which has a net charge of zero, this chemical species is an ion. . (The prefix poly- carries the meaning "many" in Greek, but even ions of two atoms are commonly described as polyatomic.)

In older literature, a polyatomic ion may instead be referred to as a radical (or less commonly, as a radical group). (In contemporary usage, the term radical refers to various free radicals, which are species that have an unpaired electron and need not be charged.)

 NH₃ substances does not dissociate to give hydrogen ions on dissolving in water.