Halides And Hydrides Of Alkali

The reducing power of alkali metals increases as we move down the group. Therefore, the correct order of reducing power is: This order is because lithium has the highest ionization energy and hence the greatest ability to reduce other substances.

- Statement I: is used in whitewash. This is true as calcium hydroxide is commonly used for whitewashing walls. - Statement II: is used as a mild abrasive in toothpaste. This is also true, as calcium carbonate is a mild abrasive used in toothpaste. Thus, both statements are correct.

In the given reaction, we can identify the type of reaction occurring. The reaction follows the mechanism of an electrophilic aromatic substitution reaction, where the alkyl group reacts with the benzene ring. The presence of and suggests that a Friedel-Crafts alkylation is taking place, where the alkyl group is added to the aromatic ring.
- The compound is likely an alkene, which will undergo the reaction with bromine ( ) to form a more reactive species in the presence of aluminum chloride ( ).
- The presence of chromium trioxide ( ) is typically involved in such transformations when reacting with an alkene to form a product that undergoes Friedel-Crafts alkylation.
Thus, the correct sequence of reactions involves chromium trioxide ( ) to form the alkylated product.

Step 1: Analyze Lithium Alloys:
Lithium forms several important alloys with other metals:

• Li + Pb (Lead): Known as 'white metal', used for manufacturing bearings for motor engines.
• Li + Al (Aluminium): High tensile strength and lightness, used in aircraft construction.
• Li + Mg (Magnesium): Extremely light and tough. This alloy is specifically used for making armour plates and thermonuclear fusion research components.

Step 2: Identify X:
The question asks for the component used to make armour plates. Based on the uses, X corresponds to Magnesium ( ).
Step 3: Final Answer:
X is Magnesium (Option C).

Step 1: Identify X (Interneuronal Transmission):
The transmission of nerve impulses across a synapse (interneuronal transmission) relies heavily on the influx of Calcium ions ( ) into the presynaptic neuron. This triggers the release of neurotransmitters (like acetylcholine) from synaptic vesicles into the synaptic cleft. Thus, X is Calcium.
Step 2: Identify Y (Sugar Transport):
The transport of sugars (like glucose) and amino acids into cells (e.g., intestinal epithelial cells) occurs via secondary active transport. This process is driven by the concentration gradient of Sodium ions ( ). The transporter protein (SGLT) co-transports sodium and glucose into the cell. Thus, Y is Sodium.
Step 3: Conclusion:
X is Calcium ( ) and Y is Sodium ( ). This matches Option (B).

1. Statement I: Lithium halides (e.g., LiCl) have covalent character due to Li 's high charge density (Fajans' rule), making I correct.
2. Statement II: NaNO decomposes on heating to NaNO + O , not NO , so II is incorrect.
3. Statement III: LiHCO is not stable as a solid; it exists in aqueous solution, unlike other alkali bicarbonates, so III is incorrect.
4. Statement IV: Only Li, Na, K form ethynides (e.g., Li C ) with ethyne; Rb, Cs do not, so IV is incorrect.
5. Thus, only I is correct, so the answer is (3) I only.

• Melting points in group 2: Be > Mg > Ca > Sr > Ba.
• Ba is largest atom, metallic bonding weakest → lowest melting point.

1. A. CaCO : Used as an antacid to neutralize stomach acid, correct.
2. B. CaO: Key ingredient in cement production (forms clinker), correct.
3. C. Ca(OH) : Used in mortar, not directly in glass making (which uses Na CO , CaCO ), so incorrect.
4. D. CaSO H O (plaster of Paris): Used as a filler in cosmetics and other industries, correct.
5. Thus, A, B, D are correct, so the answer is (1) A, B, D only.

• NaHCO decomposes releasing CO → fire extinguisher.
• Na CO precipitates Ca , Mg → water softening.
• NaOH reacts with Al O in bauxite → purification.