Iron (III) phosphate has the formula Fe2(PO4)3. What is the valency of a phosphate ion?

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Question 5: The chemical formula for ammonium sulfate. Step 1: Identify the ions involved. The ammonium ion is $\text{NH}_4^+$ and the sulfate ion is $\text{SO}_4^{2-}$. Step 2: Balance the charges to form a neutral compound. Since ammonium has a +1 charge and sulfate has a -2 charge, two ammonium ions are needed for every one sulfate ion. Step 3: Write the formula. $(NH_4)_2SO_4$ Comparing this with the options, option B is the correct formula.

The final answer is $\boxed{B}$

Question 6: The atom P and Y have the same... Step 1: Analyze the question and options. The question is incomplete, but it asks what two atoms P and Y have in common. This often refers to relationships like isotopes, isobars, or isotones. Step 2: Consider the most common interpretation in chemistry. If P and Y are isotopes (atoms of the same element with different numbers of neutrons), they must have the same number of protons. The number of protons defines the element. Step 3: Evaluate the options based on this interpretation. • A. Nucleon number (mass number): Same for isobars. • B. Number of electrons: Can be same for isoelectronic species (ions or atoms). • C. Number of neutrons: Same for isotones. • D. Number of protons: Same for isotopes (atoms of the same element). Assuming the question implies P and Y are isotopes or atoms of the same element, they would have the same number of protons.

The final answer is $\boxed{D}$

Question 7: Iron (III) phosphate has the formula $\text{Fe}(PO_4)_x$. What is the valency of a phosphate ion? Step 1: Determine the charge of the iron ion. Iron (III) indicates that the iron ion is $\text{Fe}^{3+}$. Step 2: Determine the charge of the phosphate ion. For a neutral compound, the total positive charge must balance the total negative charge. In Iron(III) phosphate, the formula is $\text{FePO}_4$, meaning $x=1$. Step 3: Since there is one $\text{Fe}^{3+}$ ion, the single phosphate ion ($\text{PO}_4$) must have a charge of -3 to balance it. The valency is the magnitude of this charge. The valency of the phosphate ion is 3.

The final answer is $\boxed{C}$

Question 8: Which one of the following is not an example of a mineral acid? Step 1: Define mineral acids. Mineral acids (or inorganic acids) are derived from inorganic compounds and typically do not contain carbon (with some exceptions like carbonic acid). Step 2: Evaluate each option: • A. Sulphuric acid ($\text{H}_2SO_4$): A common mineral acid. • B. Nitric acid ($\text{HNO}_3$): A common mineral acid. • C. Hydrochloric acid ($\text{HCl}$): A common mineral acid. • D. Citric acid ($\text{C}_6H_8O_7$): An organic acid found in citrus fruits, characterized by carboxyl groups. Step 3: Identify the acid that is not a mineral acid. Citric acid is an organic acid.

The final answer is $\boxed{D}$

Question 9: Which of the following reaction represents the reaction between magnesium and aqueous copper (II) sulphate? Step 1: Identify the reactants and type of reaction. Magnesium ($\text{Mg}$) is a metal, and copper(II) sulfate ($\text{CuSO}_4$) is an aqueous salt solution. This is a single displacement reaction because magnesium is more reactive than copper. Step 2: Predict the products. Magnesium will displace copper from the solution, forming magnesium sulfate and solid copper. The balanced chemical equation is: $\text{Mg(s)} + CuSO_4(aq) \rightarrow MgSO_4(aq) + \text{Cu(s)}$ The net ionic equation is: $\text{Mg(s)} + Cu^{2+}(aq) \rightarrow Mg^{2+}(aq) + \text{Cu(s)}$ Step 3: Compare with the given options. • A. $\text{Mg(s)} + CuSO_4(aq) \rightarrow Mg^{2+}(aq) + \text{Cu(s)}$: This option correctly shows magnesium displacing copper(II) ions. The sulfate ion is a spectator ion and is omitted from the product side, which is consistent with a net ionic representation. • B. $\text{Mg}^{2+} + Cu(s) \rightarrow Mg(s) + Cu^{2+}$: This is the reverse reaction and would not occur spontaneously. • C. $\text{Mg}^{2+} + SO_4^{2-} \rightarrow MgSO_4\text{(aq)}$: This shows the formation of magnesium sulfate from its ions, not the displacement reaction. • D. $\text{Mg(s)} + SO_4^{2-}(aq) \rightarrow MgSO_4\text{(aq)}$: This is incorrect as magnesium reacts with copper ions, not sulfate ions directly in this context.

The final answer is $\boxed{A}$

Question 10: Acids are substances that can turn... Step 1: Recall the properties of acids with common indicators. Acids are known to change the color of certain indicators. Step 2: Evaluate the options based on indicator properties: • A. Blue litmus paper red: Acids turn blue litmus paper red. This is a characteristic property of acids. • B. Red litmus paper blue: Bases turn red litmus paper blue. • C. Neutral litmus paper red: Neutral litmus paper is typically purple; acids would turn it red. However, "blue litmus paper red" is the most precise and common statement. • D. Universal indicator blue: Universal indicator turns blue in alkaline (basic) solutions, not acidic ones. In acidic solutions, it turns red, orange, or yellow.

The final answer is $\boxed{A}$