Question

Write the common names of 'X', 'Y' and 'Z', and the chemical formula of 'Y'.

Answer 1

Step 1: Identify the substances and their roles:
We are given three common substances with labels X, Y, and Z. Let’s define each one with its common name and chemical nature.

Step 2: Substance 'X' – Tartaric acid:
- Common name: Tartaric acid
- Source: Naturally found in tamarind, grapes, and other fruits.
- Nature: A weak organic acid used in baking to react with baking soda.

Step 3: Substance 'Y' – Baking soda:
- Chemical name: Sodium bicarbonate
- Chemical formula: NaHCO₃
- Use: Acts as a mild base and releases CO₂ gas when heated or when it reacts with an acid.

Step 4: Substance 'Z' – Baking powder:
- Definition: A mixture of baking soda (Y) and tartaric acid (X).
- Use: Used in baking to produce carbon dioxide gas, which makes cakes and other baked goods rise.

Step 5: Conclusion:

• ‘X’: Tartaric acid – A weak organic acid
• ‘Y’: Baking soda (NaHCO₃) – A mild base
• ‘Z’: Baking powder – A mixture of tartaric acid and baking soda

Answer 2

Step 1: Preparation of Baking Soda (NaHCO₃):
Baking soda is prepared by the Solvay process. In this process, the following reactants are used:
- Sodium chloride (NaCl)
- Water (H₂O)
- Carbon dioxide (CO₂)
- Ammonia (NH₃)

The chemical reaction involved is:
\[ \text{NaCl} + \text{H}_2\text{O} + \text{CO}_2 + \text{NH}_3 \rightarrow \text{NaHCO}_3 + \text{NH}_4\text{Cl} \]
This produces sodium bicarbonate (NaHCO₃), commonly known as baking soda.

Step 2: Use of baking soda in baking:
- Baking soda is used as a leavening agent in baking.
- When it is heated or mixed with a weak acid such as tartaric acid, it undergoes decomposition.

Step 3: Chemical decomposition reaction:
\[ 2\text{NaHCO}_3 \xrightarrow{\text{Heat}} \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2 \uparrow \]
This reaction releases carbon dioxide gas (CO₂).

Step 4: Role of CO₂ in making cakes soft and spongy:
- The released CO₂ forms bubbles in the dough or batter.
- These bubbles expand when heated, causing the dough to rise.
- As a result, the texture becomes soft and spongy.

Conclusion:
Baking soda is prepared by the Solvay process. In baking, it releases CO₂ gas upon heating or reacting with an acid, which makes the cake soft and spongy by forming bubbles in the batter.

Answer 3

Step 1: Understand the role of antacids:
- Antacids are substances used to relieve acidity or heartburn caused by excess hydrochloric acid in the stomach.
- They work by neutralizing the excess acid and providing quick relief.

Step 2: Identify the type of substance used:
- Antacids are typically mild bases because strong bases can be harmful to body tissues.

Step 3: Name a common mild base used as an antacid:
- One widely used mild base (other than 'Y') is Magnesium hydroxide.

Step 4: Write the chemical formula:
- The chemical formula of Magnesium hydroxide is Mg(OH)₂.

Step 5: Common name and usage:
- Magnesium hydroxide is commonly known as Milk of Magnesia.
- It is safe and effective in neutralizing stomach acid.

Conclusion:
A mild base used as an antacid is Magnesium hydroxide (Mg(OH)₂), also known as Milk of Magnesia.

Answer 4

Step 1: Understand the question:
We are asked to identify the type of circuit used for operating different electrical gadgets in a household and explain why that type is preferred.

Step 2: Identify the type of circuit:
The type of circuit used in homes is a parallel circuit.

Step 3: Reason 1 – Equal voltage supply:
- In a parallel circuit, all devices are connected directly to the main voltage source.
- This means each electrical gadget receives the same voltage as the source (e.g., 220 V in homes).
- This ensures that every appliance runs efficiently and performs as intended.

Step 4: Reason 2 – Independent operation:
- In a parallel circuit, each gadget is connected in a separate branch.
- If one device fails or is switched off, the other devices continue to work because the current in other branches is unaffected.
- This enhances safety and convenience in household electrical systems.

Step 5: Conclusion:
Type of circuit: Parallel circuits should be used to operate different electrical gadgets at home.
Reasons:
1. Each gadget gets the same voltage as the source.
2. Failure of one gadget does not affect the operation of others.

Answer 5

Step 1: Analyze the circuit and identify resistor combinations:
The given circuit includes the following resistors:
- Two 6 Ω resistors are connected in parallel.
- Two 3 Ω resistors are connected in series with the equivalent of the 6 Ω parallel combination.

Step 2: Calculate the equivalent resistance of the parallel resistors:
When two resistors \( R_1 \) and \( R_2 \) are in parallel, the combined resistance \( R_{\text{parallel}} \) is given by:
\[ \frac{1}{R_{\text{parallel}}} = \frac{1}{R_1} + \frac{1}{R_2} \]
Substitute the values:
\[ \frac{1}{R_{\text{parallel}}} = \frac{1}{6} + \frac{1}{6} = \frac{2}{6} = \frac{1}{3} \]
\[ R_{\text{parallel}} = 3\,\Omega \]
So, the two 6 Ω resistors in parallel are equivalent to a single 3 Ω resistor.

Step 3: Add the resistors in series:
Now, we add the two 3 Ω resistors in series with the 3 Ω equivalent resistance we just found:
\[ R_{\text{total}} = 3\,\Omega + 3\,\Omega + 3\,\Omega = 9\,\Omega \]
So, the total resistance of the circuit is 9 Ω.

Step 4: Apply Ohm’s Law to find the total current:
Ohm’s Law is given by:
\[ I = \frac{V}{R} \]
Where:
- \( V = 4.5\,\text{V} \) (the total voltage from the source)
- \( R_{\text{total}} = 9\,\Omega \) (the total resistance in the circuit)

Substitute the values:
\[ I = \frac{4.5}{9} = 0.5\,\text{A} \]

Step 5: Conclusion:
The total current flowing through the circuit is 0.5 A.