Question

1. which of the following liquids is a good conductor of electric current? a. glucose solution b. ethanol c. potassium chloride solution d. petrol 7. what mass of magnesium oxide is required to neutralize 25.0 cm³ of 0.1 mol dm⁻³ hydrochloric acid? mgo = 40, hcl = 36.5 a. 0.025 g b. 0.100 g c. 0.050 g d. 0.250 g 8. which of the following atoms would lose electrons most readily? a. aluminium b. sodium c. chlorine d. silicon 9. ethane does not undergo addition reaction because it a. is an organic substance. b. decolourizes bromine water. c. is a saturated hydrocarbon. d. is an unsaturated hydrocarbon. 10. consider the following reaction equation: 2x(s) + cl₂(g) → 2xcl(s) which group of elements does x belong? a. group i b. group iii c. group ii d. group iv 11. consider the following reaction equation: cuso₄(aq) + 2naoh(aq) → cu(oh)₂(s) + na₂so₄(aq) this is an example of a/an a. substitution reaction. b. neutralization reaction. c. double decomposition reaction. d. addition reaction. 12. which of the following gases is produced when calcium hydroxide is heated with solid ammonium chloride? a. nh₃ b. h₂ c. cl₂ d. o₂

Explanation:

Step1: Identify good conductors

Good conductors of electric - current are substances that dissociate into ions in solution. Glucose and ethanol are covalent compounds and do not dissociate into ions. Petrol is a mixture of hydrocarbons and is non - conducting. Potassium chloride ($KCl$) is an ionic compound and dissociates into $K^+$ and $Cl^-$ ions in solution, making it a good conductor.

Step2: Solve for mass of magnesium oxide

First, write the balanced chemical equation: $MgO + 2HCl=MgCl_2 + H_2O$.
The number of moles of $HCl$, $n(HCl)=c\times V$, where $c = 0.1\ mol\ dm^{- 3}$ and $V = 25.0\ cm^{3}=0.025\ dm^{3}$. So $n(HCl)=0.1\times0.025 = 0.0025\ mol$.
From the stoichiometry, the mole ratio of $MgO$ to $HCl$ is $1:2$. So the number of moles of $MgO$, $n(MgO)=\frac{1}{2}n(HCl)=\frac{0.0025}{2}=0.00125\ mol$.
The molar mass of $MgO$ is $M = 40\ g/mol$. The mass of $MgO$, $m=n\times M=0.00125\times40 = 0.050\ g$.

Step3: Determine atom that loses electrons readily

Metals tend to lose electrons. Among the given options, sodium is the most electro - positive metal. It has a single electron in its outermost shell and has a strong tendency to lose this electron to achieve a stable noble - gas configuration.

Step4: Analyze addition reaction of ethane

Addition reactions occur in unsaturated hydrocarbons. Ethane is a saturated hydrocarbon ($C_2H_6$) with only single bonds between carbon atoms, so it does not undergo addition reactions.

Step5: Identify group of element X

From the reaction $2X + Cl_2
ightarrow2XCl$, the element $X$ forms a monovalent chloride. Elements in Group I form monovalent chlorides.

Step6: Classify the reaction

In the reaction $CuSO_4+2NaOH
ightarrow Cu(OH)_2 + Na_2SO_4$, the positive and negative ions of two compounds exchange places. This is a double - decomposition reaction.

Step7: Determine gas produced

When calcium hydroxide ($Ca(OH)_2$) is heated with solid ammonium chloride ($NH_4Cl$), the reaction is $Ca(OH)_2 + 2NH_4Cl
ightarrow CaCl_2+2NH_3 + 2H_2O$. The gas produced is ammonia ($NH_3$).

Answer:

1. C. Potassium chloride solution
2. C. 0.050 g
3. B. Sodium
4. C. is a saturated hydrocarbon
5. A. Group I
6. C. double decomposition reaction
7. A. $NH_3$