NEET Chemistry Questions: Redox Reactions & Electrochemisty

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What is the oxidation No. of Cr in $ CrO_5, K_2Cr_2O_7, K_2CrO_4 $ or in chromium pentoxide , potassium dichromate, potassium chromate respectively




The oxidation number of chromium in CrO5, K2Cr2O7, and K2CrO4 are +6, +6, and +6, respectively. This can be determined by using the rules for oxidation states and the known structures of these compounds. For example, in K2Cr2O7 (potassium dichromate), chromium is in the +6 oxidation state due to the balancing of charges with oxygen and potassium.
What is the oxidation no. of phosphorus in $ H_3PO_3, H_3PO_4, H_3PO_2$ or phosphorus, acid, Phosphoric acid, phosphinic acid respectively ?




No explanation available.
What is the oxidation no. of phosphorus in $ H_4P_2O_7, H_5P_3O_{10}, (HPO_3)_3 $ or pyrophosphoric acid, penta phosphoric acid, triphosphoric acid respectively ?




To determine the oxidation number of phosphorus in each compound, we follow these steps: For $H_4P_2O_7$ (pyrophosphoric acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - The overall charge of the compound is 0. - Let the oxidation number of phosphorus be x. $4(+1) + 2(x) + 7(-2) = 0$ $4 + 2x - 14 = 0$ $2x - 10 = 0$ $2x = 10$ $x = 5$ For $H_5P_3O_{10}$ (penta phosphoric acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - The overall charge of the compound is 0. - Let the oxidation number of phosphorus be x. $5(+1) + 3(x) + 10(-2) = 0$ $5 + 3x - 20 = 0$ $3x - 15 = 0$ $3x = 15$ $x = 5$ For $(HPO_3)_3$ (triphosphoric acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - The overall charge of the compound is 0. - Let the oxidation number of phosphorus be x. $3(+1) + 3(x) + 9(-2) = 0$ $3 + 3x - 18 = 0$ $3x - 15 = 0$ $3x = 15$ $x = 5$ Thus, the oxidation numbers are +5 for $H_4P_2O_7$, +5 for $H_5P_3O_{10}$, and +5 for $(HPO_3)_3$.
The oxidation no. of chlorine in $ HClO, HClO_2, HClO_3, HClO_4 $ or Hypochlorus acid, chloric acid, chloric acid and perchloric acid respectively are




To determine the oxidation number of chlorine in each compound, we follow these steps: For $HClO$ (hypochlorous acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - Let the oxidation number of chlorine be x. $1(+1) + x + 1(-2) = 0$ $1 + x - 2 = 0$ $x - 1 = 0$ $x = +1$ For $HClO_2$ (chlorous acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - Let the oxidation number of chlorine be x. $1(+1) + x + 2(-2) = 0$ $1 + x - 4 = 0$ $x - 3 = 0$ $x = +3$ For $HClO_3$ (chloric acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - Let the oxidation number of chlorine be x. $1(+1) + x + 3(-2) = 0$ $1 + x - 6 = 0$ $x - 5 = 0$ $x = +5$ For $HClO_4$ (perchloric acid): - Hydrogen has an oxidation number of +1. - Oxygen has an oxidation number of -2. - Let the oxidation number of chlorine be x. $1(+1) + x + 4(-2) = 0$ $1 + x - 8 = 0$ $x - 7 = 0$ $x = +7$ Thus, the oxidation numbers are +1 for $HClO$, +3 for $HClO_2$, +5 for $HClO_3$, and +7 for $HClO_4$.
What is the oxidation no. of iodine in $ ICl_3, CsI_3 $ respectively ?




No explanation available.
What is the maximum positive oxidation state of halogen element in any of it’s compound ?




Halogens are elements in Group 17 of the periodic table, and they can exhibit various oxidation states. The maximum positive oxidation state of a halogen is +7, which is seen in compounds like potassium permanganate (KMnO_4) where chlorine can be +7 in perchlorates (ClO_4^-). This is because halogens can lose up to seven electrons from their valence shell.
What is the maximum positive oxidation state of chalcogen element in it’s compound ?




Chalcogens are elements in Group 16 of the periodic table, which includes oxygen, sulfur, selenium, tellurium, and polonium. The maximum positive oxidation state of chalcogens is +6. This is seen in compounds like sulfur hexafluoride (SF_6) and sulfuric acid (H_2SO_4), where sulfur exhibits an oxidation state of +6.
What is the the oxidation no. of nitrogen in $ N_3H, H_2N_2O_2, HNO_3 $ or hydrazoic acid, hyponitrons acid, nitrus acid, nitric acid respectively ?




To find the oxidation number of nitrogen in each compound, we can use the rule that the sum of oxidation numbers in a neutral compound is zero and in a polyatomic ion is equal to the charge of the ion. For $N_3H$ (hydrazoic acid), let the oxidation number of nitrogen be x. The oxidation number of hydrogen (H) is +1. The equation is: $3x + 1 = 0 \Rightarrow x = -1/3$. For $H_2N_2O_2$ (hyponitrous acid), let the oxidation number of nitrogen be y. The oxidation numbers of hydrogen and oxygen are +1 and -2 respectively. The equation is: $2(+1) + 2y + 2(-2) = 0 \Rightarrow 2y - 2 = 0 \Rightarrow y = +1$. For $HNO_3$ (nitric acid), let the oxidation number of nitrogen be z. The oxidation numbers of hydrogen and oxygen are +1 and -2 respectively. The equation is: $+1 + z + 3(-2) = 0 \Rightarrow z - 5 = 0 \Rightarrow z = +5$. Therefore, the correct oxidation numbers are: –1/3, +1, +3, +5.
What is the oxidation no. of silicon in zeolite $ (Na_2Al_2Si_4O_{12}) and tremolite [(Ca_2 Mg_5(OH)_2(Si_4O_{11})_2]$ respectively ?




Zeolites are aluminosilicate minerals and tremolite is a type of inosilicate. In zeolite $Na_2Al_2Si_4O_{12}$, each silicon (Si) atom typically has an oxidation state of +4. In tremolite $Ca_2Mg_5(OH)_2(Si_4O_{11})_2$, each silicon (Si) atom also has an oxidation state of +4. Therefore, the correct answer is +4, +4.
The value of n in $ AlF_xOy^n$ is




In the given compound $AlF_xOy^n$, aluminum (Al) has a fixed oxidation number of +3. The oxidation number of fluorine (F) is -1, and oxygen (O) is -2. According to the rules for oxidation states, the sum of the oxidation numbers must equal the charge of the ion or molecule. The equation can be set up as: $+3 + x(-1) + y(-2) = n$. Simplifying, we get $3 - x - 2y = n$. Therefore, the value of n is $+3 - x - 2y$.
The value of n in $ AlF_XO_Y^n $ , if x=1 and y=1 ?




No explanation available.
The value of n in $ AlF_XO_Y ^n$ , if x=2 and y=3




No explanation available.
What will be the value of x and y respectively in $ AlF_XOy^{6–} ? $




No explanation available.
How many moles of elements are added when 2.5 mole $ Cr_2O_7 ^{2–} reduced in Cr^{3+} $ ?




When $Cr_2O_7^{2-}$ is reduced to $Cr^{3+}$, the half-reaction is: $$Cr_2O_7^{2-} + 14H^+ + 6e^- ightarrow 2Cr^{3+} + 7H_2O$$. For 2.5 moles of $Cr_2O_7^{2-}$, the moles of electrons added can be calculated by multiplying 2.5 by the number of electrons involved per mole of $Cr_2O_7^{2-}$: $$2.5 imes 6 = 15 ext{ moles of electrons}$$.
What moles of $Cr_2O_7 ^{2–} reduced in Cr^{3+} $ by the addition of 12 moles of electrons ?




Using the same half-reaction: $$Cr_2O_7^{2-} + 14H^+ + 6e^- ightarrow 2Cr^{3+} + 7H_2O$$. To find the moles of $Cr_2O_7^{2-}$ reduced by 12 moles of electrons, we set up the proportion: $$ rac{12 ext{ moles of } e^-}{6 ext{ moles of } e^-} = 2 ext{ moles of } Cr_2O_7^{2-}$$.