Explanation​:
NaOH is a strong base and so would release a high concentration of OH^− ions in water. Choices A and C are incorrect as HCl and H2SO4 are strong acids and would give low $\mathrm{pH}$s. $\mathrm{NaCl}$ is a neutral salt.

Explanation:
Use the mnemonic CNAP; cathode negative, anode positive for the polarity in electrolytic cells.

Explanation:​
C3H8​ is a saturated alkane and C3H6​ is an unsaturated alkene. The test of unsaturation using Br2(aq) can demonstrate the presence or absence of a carbon-carbon double bond.
In the presence of a double bond, Br2(aq) can add across the double bond in the alkene producing a dibromo-alkane, and a change of color from brown to colorless will be observed.
In the case of the absence of a double bond (saturated hydrocarbon), no color change would occur.

Explanation​:
More reactive metals are more likely to lose electrons (be oxidised) and so, Zn(s) will lose electrons to produce Zn^2+(aq) .
Cu^2+(aq)will gain electrons forming Cu(s) leading to a decrease in Cu^2+(aq) concentration and a paler blue colour of the solution.
Electrons flow from the anode(Zn) to the cathode (Cu).

Explanation:​
Assuming "x" to be the oxidation number of N:

• In nitrate NO3− , x +3 (-2) = -1. Therefore, x = +5
• In nitrite NO2− , x +2 (-2) = -1. Therefore, x = +3

Explanation​:
By definition, the more readily an acid releases a proton, the less likely the conjugate base is to accept a proton.

A

Explanation:​
NaOH is a base so reacts with a hydrogen ion. HNO3​, nitric acid, releases a hydrogen ion through the breaking (heterolysis) of the O-H bond.
This question is moderately difficult as the student must recognise that NaOH is a base and HNO3​ an acid and correctly interpret a structural formula that may be unfamiliar.

Explanation​:
Zn2+(l) gains electrons and is reduced to Zn(s) at the cathode. Cl−(l) loses electrons and is oxidised to Cl2(g) at the anode.

Explanation:​

Metals and acids react to produce a salt and hydrogen gas. The formulae of the ions are Mg2+ and NO3−, therefore for a neutral salt, two nitrate ions are required for each magnesium ion.

Explanation:​
Reducing agent is a substance that is oxidized.
Oxidation state of Zn increases from 0 to +2, whereas the oxidation state of N decreases from +5 to +4.
The oxidation state of H remains +1.
The oxidation state of O remains -2.

Explanation​:
Metal oxides produce basic solutions when dissolved in water. Non-metal oxides produce acidic solutions when dissolved in water.
Silicon dioxide does not react with water, but reacts with concentrated alkalis to form silicates: SiO2(s)+2 OH−(aq)→SiO32−(aq)+H2O(l)

Explanation:​
A tenfold decrease in [H+], leads to a $\mathrm{pH}$ increase of 1.

Explanation:
Non-spontaneous reactions take place in electrolytic cells using an external power supply.
The positive electrode is the anode where oxidation takes place.
The aqueous metal ion (Mx^+) is reduced at the cathode to produce the solid metal.

Explanation​:
Step 1 is a free radical substitution, converting the alkane to a chloroalkane and producing HCl as a by-product.
Step 2 is a nucleophilic substitution, in which the C−Cl bond breaks and is replaced by a hydroxyl (C−OH) group; the products are an alcohol and sodium chloride.
Step 3 is an oxidation. To prevent the aldehyde from being oxidised further to a carboxylic acid, the product must be removed by distillation as it forms.

Explanation:​
Oxidation state of Mn in MnO4^− is +7. The change in oxidation state is from +3 to +7.
Oxidation refers to an increase in oxidation state.

Explanation​:
Cathode site of reduction, anode site of oxidation, use CROA to remember this.
Reduction is the gain of electrons.

Explanation​:
The positive ions (cations) move in the direction of the cathode as the positive Cu2+ ions are used up.
Zn being more reactive than copper, Zn(s) is the anode where oxidation occurs, and Cu(s) is the cathode where reduction of Cu2+(aq) occur

Explanation​:
By definition an acid is a proton donor. Weak acids only partially dissociate in aqueous solution leading to poor conductivity

Explanation:​
In equation 1, the oxidation state of Cl decreases from +5 to 0 (reduced), and the oxidation state of Iodine increases from 0 to +5 ( oxidized).
In equation 2, the oxidation state of Cl increases from 0 to +1 in NaClO (oxidized), and also decreases from 0 to -1 in NaCl (reduced).

Explanation:​
$\mathrm{pH}$ = $-$.
For concentrations of H+ greater than 1 mol dm^−3, this would result in a negative $\mathrm{pH}$ value.