Chemistry Quiz Questions And Answers For Class 12

The ion Fe⁺³ has the highest magnetic moment because it has an unpaired electron in its d orbital. This unpaired electron allows Fe⁺³ to have a higher magnetic moment compared to the other ions listed. The other ions do not have unpaired electrons in their d orbitals, so their magnetic moments are lower.

FeCl2 is paramagnetic because it contains unpaired electrons. Paramagnetic substances are attracted to a magnetic field due to the presence of unpaired electrons. It is also colored because the presence of unpaired electrons allows for absorption and emission of specific wavelengths of light, resulting in a visible color.

 When the d-sublevel contains ten electrons, it means that all five d orbitals are filled with two electrons each. When the d sublevel contains eight electrons, four orbitals are filled with two electrons each.

Titanium (III) ion has a lower oxidation state compared to titanium (IV) ion. This means that titanium (III) ion has a greater tendency to lose electrons and be oxidized. Therefore, it is easy to convert titanium (III) ion to titanium (IV) ion by oxidizing it through the loss of electrons.

ScCl3 is the correct answer because it is not paramagnetic and colored. Paramagnetic compounds contain unpaired electrons, which are attracted to a magnetic field, while colored compounds absorb certain wavelengths of light, resulting in their distinct color. FeCl3 and CoCl2 are both paramagnetic and colored, while CuCl2 is paramagnetic but not colored. ScCl3, on the other hand, does not have any unpaired electrons and therefore is not paramagnetic. Additionally, it does not exhibit any distinct color.

Copper (Cu) has the highest ability to conduct electricity among the given elements. This is because copper has a high electrical conductivity due to its atomic structure. It has a large number of free electrons in its outermost energy level, which allows for easy movement of electric charge. On the other hand, titanium (Ti), nickel (Ni), and iron (Fe) have lower electrical conductivity compared to copper.

Aluminum-manganese alloy is used in soft drink cans to prevent corrosion and rusting. This alloy has a high resistance to corrosion and forms a protective oxide layer on the surface of the can, preventing any reaction with the contents of the can. It is a commonly used alloy in the packaging industry due to its durability and ability to maintain the quality of the product inside the can.

The correct answer is Zn2+, all of its d-electrons are paired. This is because when all of the d-electrons in an ion are paired, it results in a colorless solution. In contrast, when the d-electrons are unpaired, it can lead to the absorption of certain wavelengths of light, causing the solution to appear colored. In the case of V3+ ions, all of its d-electrons are unpaired, which can result in a colored solution. However, in Zn2+ ions, all of its d-electrons are paired, leading to a colorless solution.

The magnetic moment of an element is determined by the number of unpaired electrons in the 3d sublevel and is described by the attraction of a compound to a magnet. This means that if an element has unpaired electrons, it will have a magnetic moment and will be attracted to an external magnet. Therefore, the correct answer is a. The presence of unpaired electrons in the 3d sublevel is a key factor in determining the magnetic properties of an element.

In a controlled experiment involving the introduction of various substances into a tube with a sensitive balance indicator, Cr3+ (Chromium III ion) would likely induce the most significant movement in the indicator. This is because Cr3+ ions typically have a higher charge density compared to ions like V2+ (Vanadium II), Fe2+ (Iron II), and Mn2+ (Manganese II). The higher charge density of Cr3+ results from its three positive charges and smaller ionic radius, which enhances its ability to interact with other molecules and particles in the environment. This stronger interaction can lead to greater influence on the balance indicator, making it move more noticeably.

The given statement suggests that the oxidation of Manganese (II) ion to Manganese (III) ion is not an easy process but rather a difficult one. This implies that it requires a significant amount of energy or specific conditions for this oxidation reaction to occur. Therefore, the correct answer is "Difficultly".

Scandium and zinc are the correct answer because they are the only two elements in the first transition series that have only one oxidation state. Scandium has an oxidation state of +3, while zinc has an oxidation state of +2. The other options, copper, nickel, and chromium, all have multiple oxidation states.

The given chemical reaction is represented by the figure. The ∆H value for this reaction is not provided in the question. However, it can be inferred that the activation energy before using the catalyst is +150 and after using the catalyst is +100. This is because the activation energy decreases when a catalyst is used, making it easier for the reaction to occur. The ∆H value and the activation energy after using the catalyst are not provided in the given options. Therefore, the correct answer cannot be determined based on the given information.

The correct answer is Non-transition element. Non-transition elements refer to elements in which the d or f sublevel is not completely filled with electrons in either the atomic state or the oxidation state. Transition elements, on the other hand, have partially filled d or f sublevels. Inner transition elements are a subset of transition elements and are located at the bottom of the periodic table. Therefore, the element where the d or f sublevel is completely filled with electrons would not be a non-transition element.

An acid is strong when it easily loses a proton in solution. When a chlorine atom gains an electron, it does not become a positively charged ion. This is because when an atom gains an electron, it becomes negatively charged, not positively charged. However, it is true that a neutral atom has equal numbers of protons and electrons

Cobalt-60 is used in the detection of industrial flaws such as cracks in welded locations. This radioactive isotope emits gamma rays, which can penetrate through materials and reveal hidden flaws. By exposing the welded area to Cobalt-60, any cracks or defects can be detected through the analysis of the gamma rays that are emitted and detected.

The ions that cannot be produced by normal chemical reactions are Sc2+ and Zn+. Scandium (Sc) typically forms a +3 ion, not a +2 ion. Zinc (Zn) typically forms a +2 ion, not a +1 ion. Therefore, Sc2+ and Zn+ cannot be produced by normal chemical reactions.

Copper(II) sulphate is used in determining the percentage of sugar in urine of diabetic patients. It is commonly used in a test called Benedict's test, which is used to detect the presence of reducing sugars such as glucose in a solution. When heated with a reducing sugar, copper(II) sulphate is reduced to copper(I) oxide, resulting in a color change from blue to green, yellow, or red, depending on the amount of sugar present. This color change is then used to determine the percentage of sugar in the urine sample.

The first ionization potential is the energy required to remove one electron from an atom in its gaseous state. It is a measure of how tightly the electrons are held by the nucleus. As we move across a period from left to right in the periodic table, the atomic radius decreases and the effective nuclear charge increases, making it more difficult to remove an electron. Nickel (Ni) is located towards the right side of the transition metal series, so it has a higher effective nuclear charge compared to the other elements listed. Therefore, it requires more energy to remove an electron from Ni, making it have the highest 1st ionization potential among the given options.

In the given question, we are asked to choose the symbol of a transition element whose magnetic moment in its atomic state and its oxidation state (+2) equal 5. The magnetic moment of an atom is determined by the number of unpaired electrons. In the case of Mn, it has 5 unpaired electrons in its atomic state and when it is in the +2 oxidation state, it still retains 5 unpaired electrons. Therefore, Mn is the correct answer as it satisfies the given condition.

As the atomic number increases, the ionization energy generally increases. This is because as the atomic number increases, the number of protons in the nucleus also increases, resulting in a stronger attraction between the nucleus and the electrons. This stronger attraction makes it more difficult to remove an electron from the atom, hence increasing the ionization energy. Therefore, the statement that the ionization energy decreases with the increase in atomic number is incorrect.

All the given chemical formulas represent real compounds except for Zn2O3. Zn2O3 does not exist in nature or in any known chemical database.

Scandium, which replaces hydrogen of water vigorously, would have a higher chemical activity than iron. Therefore, it would occupy a place before iron in the previous arrangement of elements arranged according to chemical activity.

This method involves the catalytic conversion of carbon monoxide and hydrogen into hydrocarbons. It was developed in the early 20th century by Franz Fischer and Hans Tropsch and is commonly used in the production of synthetic fuels from coal, natural gas, or biomass. The process allows for the production of a wide range of liquid hydrocarbons, including gasoline, diesel, and jet fuel, making it a versatile and important method in the fuel industry.

Copper(II) sulphate is used in getting pure drinking water in desert locations. It acts as a disinfectant and helps in killing harmful bacteria and algae in water. Copper(II) sulphate also aids in removing impurities and improving the taste of water. It is commonly used in water treatment processes to ensure the safety and quality of drinking water in arid regions.

The atomic number of an element determines the number of protons in its nucleus. In the first transition series, the elements have atomic numbers ranging from 21 to 30. The magnetic moment in X2O3 compound equals 3 indicates that the element has three unpaired electrons. Based on the electron configuration of transition metals, an element with three unpaired electrons would have an atomic number of 24, which corresponds to chromium (Cr). Therefore, the correct answer is 24.

The correct arrangement of the oxidation numbers in these oxides is L

Transition metals are characterized by their ability to conduct electricity. This is due to the presence of free electrons in their outermost energy level, which can move freely and carry an electric current. This property is not commonly found in other elements, making it a distinguishing feature of transition metals.

Copper is a transition element in the first transition series that has an oxidation number higher than its vertical group number. In the first transition series, the vertical group number represents the maximum oxidation state that an element can have. Copper, however, can have an oxidation state of +2 or +1, which is higher than its group number of +1. This is due to the presence of partially filled d-orbitals in its electron configuration, allowing for different oxidation states.